1. it wasn't a lot of beneficial mutations, when it comes to intelligence specifically, most of the responsibility is mutations that rendered functional genes non-functional. Namely, a gene that helped control cell division in brain cells, and one for the formation of a jaw muscle. Without the former, organisms within the human lineage had their brains grow at an extreme rate, which lead not only to increased intelligence, but an increase in brain cancer risk. It just so happens that the benefit of increased intelligence outweighed the detriment of cancer being more common in the population. Without the latter, the skull size was less restricted, as the jaw muscle in question made skull growth limited as a physical barrier. This allowed more space for a larger brain, with the consequence of resulting in weaker jaws as well.
2. Our intelligence isn't like a god's, especially not like the Christian god's. This being is supposedly omniscient; something physically impossible for a human to even be close to, even if one had access to books which contained all there is to know. We can't remember enough information, no matter how much time we'd have to read and memorize.
