I'm interested to know how a Roman Catholic "uses" a cross. What does it help you do?
If I may give my own answer:
In the Judeo-Christian tradition, we believe that the thing you're wearing right now, that body of yours, we believe it's indispensable to your being. "Essential", if you will. Obviously your current one is soulish and will need to be reconstituted, but having one is indispensable nonetheless.
If you're bold enough, you may go so far as to say that you *are* a body. That you cannot hope to encounter anything at all, or perform the Divine Service for which you were created, without your body, being that you are one.
If we have accepted these things, that human existence, and Divine Service to God, involve the body, then what a human being does with the body matters. These acts must have the possibility of being of eternal and essential significance to God and men and creation.
Therefore, when the Scriptures speak of the workings of the inner man, inner wisdom of the heart, the spirit, the soul, these *must*, in the sanctified man, shine forth bodily. And so we cannot embrace dualistic dichotomies between "the soul" and "what is done in the body". Nor can we interpret "heartfelt prayer" to mean "intellectual process" contrasted to what is material, set aside as merely "meaningless ritual" or "stuff made by hands that is therefore garbage".
For the Apostle says: "Whether therefore ye eat, or drink, or whatsoever ye do, do all to the glory of God."
And "present your bodies a living and holy sacrifice, acceptable to God, which is your Rational Divine Service."
Now that we have that out of the way, what does the Cross do?
The Cross is made of matter, the symbolon (coming together) through which the salvation of the world, material and spiritual, was performed by Christ. It re-capitulates all of the saving acts of Christ, and his ruling power, and his kingship. So to form a Cross from matter is to sanctify matter through its use in the name of Christ, which is something that is worthy and proper for humans to do.
Now, you have a Cross, which is the symbol and re-presentation (meaning it actually makes present) the ruling and conquering power of Christ. So the Cross is used for the crushing of adverse powers, the sanctification and blessing of matter, the proclamation of the Reign of God, the blessing and coming together of humans in Christ, the call to repentance, the remembrance of the Sacrifice, and many other things that we can attain to through Christ and by the indwelling of the Holy Spirit, to the glory of God our Father.