What would you say of all of these people and their handed down traditions of thinking of man; are the beneficiary to the cause and purpose to the kingdom of God in any way by chance?
I would deny these are traditions of men, but rather represent the Holy Spirit at work in the Church over time, and this is specifically some the fruits of the Spirit produced by the Eastern Orthodox, Oriental Orthodox and Assyrian Church of the East over 2,000 years, most of which were spent being persecuted by the Roman Empire, the pre-Christian governments of the Slavic lands, Caucasia, Muslims, Communists, Hindus (in addition to the active persecution of Christians in India by Hindus and Muslims, despite Christians being the third largest religion and twice the size of the Sikhs and Jains, they will not fight back like the Sikhs and are not revered like the Jains outside of Malankara, it was a Hindu who martyred Thomas the Apostle in 53 AD, but the Church of India still exists, and in Kerala, which was until the formation of the State of Israel the population center of Indian Jews, like the Sassoon family (Vidal Sassoon being the most famous Keralan Jew), is to be found what is probably the only surviving church building from the first century), Buddhists (who it appears assisted Tamerlane in his genocide of the Christians in China, Mongolia and Tibet), the Mongolian Khanates, the Turks, Islamic fundamentalists, ISIS, and so on. The blood spilled by Eastern Christians represents more of this fruit.
There is also much spiritual fruit in terms of theology, mystical and intellectual, from both the pre-schism pan-Chalcedonian, post-schism* Roman Catholic, and Protestant dimensions of the Western Church, like Irish monasticism, Benedictine scholasticism which gave us Universities and Higher Learning (Oxford and Cambridge were originally monasteries), Scholastic theology, pre-Reformation mystical theology, such as Carthusian and Cistercian monasticism and Carmelite, Franciscan, Dominican, Augustinian and Servite religious living , then the enormous event that was the Reformation, which I think helped tje Roman Catholic Church purify itself of many corrupt elements during the Council of Trent, like the sale of indulgences, even as the Western churches were freed from Papal supremacy.
Post-reformation Western mystical theology occurs in both Roman Catholic (St. Francis de Sales, St. Philip Neri, St. John of the Cross, to name a few) and Protestant forms (Count Zinzendorf, the protector of the Moravians, John and Charles Wesley, who were indirectly influenced by the Moravians and their fusion of his mystical theology with Eastern Orthodox, Lutheran and indigenous Czech Reformation theology, and among Lutherans, the great Danish mystic Soren Kierkegaard, among many others, such as some of the Lutheran Pietists, as well as more extreme mystical theologians such as George Fox, the founder of the Quakers, who was definitely Christian but had a radical idea about worship, and the related Quietist tradition).
And plenty of Western Christians died at the hands of Muslims, Communists, and in the mission fields over the years, and many more were killed.
So mystical theology has both an Eastern and Western component.
I am more interested in the Eastern component, because of my interest in theology as prayer, and the definition of theology as knowledge of God, and the consistency of Orthodox Hesychast views such as the unknowability of the Divine Essence, his knowability through His Incarnation in the person of the Son,” and constant prayer with a literal interpretation of Scripture (John 1:18 and 1 Thessalonians 5:17).
But in either case, the fruit of the spirit evident in the Eastern church, such as the martyrdoms, the resilience of faith in spite of persecution, the preservation of Patristic tradition, such as the ancient models of theology, the ancient hymns and liturgies, the canon law of the early church (Rome has rewritten its canon law repeatedly, as have most Protestant churches, and some of the ancient canons, such as those prohibiting ministers from hitting, slapping or striking anyone for any reason, and from managing the financial affairs of their congregants, are extremely wise and should be adopted by every church), and also the ability of the Eastern churches to avoid ever experiencing as disruptive event, and as bloody an event owing to the subsequent Wars of Religion, as the Protestant Reformation, which was itself needed to free the Roman church of the corruption of the Borgias and their successors, but which cost a very high price in human suffering and death - this never happened in the Eastern church because no Eastern church ever found itself in a predicament with hierarchical corruption like the Western church found itself in during the High Renaissance, this all helps to legitimize Eastern mystical theology, because mystical theology is fundamental to the Eastern church.
Would there be or are there any dangers with the use of them?
Actually, in some cases, primarily for monastics, yes, and the Eastern Orthodox authors who write on Hesychasm warn about this; about half of the
Philokalia consists of ascetics warning others of the dangers of pride and spiritual delusion. This is also the central theme in the
Ladder of Divine Ascent, written for monastics but widely read by the laity, and more recently,
The Arena, by Ignatius Brianchaninov.
But the same author wrote
On The Prayer of Jesus for the laity, and for the laity who pray the Jesus Prayer as part of their prayer life (“Lord Jesus Christ, Son of God, Have Mercy on Me, a Sinner”, this is completely harmless, being taken from two Gospel verses, and its regular prayer, or the prayer of the shortened version common to both East and West, “Lord have Mercy” (Kyrie Eleison), along with the reverential use of the Lord’s Prayer, which we know from the Didache that early Christians recited times daily, is extremely beneficial, and more accessible to most Protestants than the Rosary.
* I refer of course to the Great Schism of 1054, in which the Roman Catholics began to break communion with the Eastern Orthodox over the refusal of the Orthodox to submit to Papal Supremacy, a process that was concluded with the persecution of the Orthodox, who were sometimes victims of cannibalism, in the Crusades, and the subsequent rejection by the laity of the re-union with Rome on Roman Catholic terms negotiated and supported by most of the Greek Orthodox bishops at the Council of Florence in the 1430s, a rejection made in the knowledge that it would lead to the conquest Constantinople and the remaining Byzantine lands by the Ottoman Empire, and the brutal subjugation of the populace by the Muslims.