What if we meet extraterrestrial life? Would we ban them from showing us all the math they already solved and/or invented?
The societal rewards of the mathematical community's pursuit of answers to problems is not primarily in the answers themselves. It is in the practical problems that are eventually solved not by knowing the solution to the initial problem but by means of the new branches of mathematics that were invented to solve it.
Are you really unfamiliar with the concept that "the journey is the destination"? Read a book.