I just think it's crazy to think that no one will ever ask, "what's the purpose of taking over all these galaxies?"

If asked, they might answer along the lines of "so that more people can exist and be happy"; "so that ever more interesting and fun and beautiful patterns can come into being"; "so that we can continue to learn and understand more and more of the strange and wonderful patterns of reality", etc. None of these are magical answers; they can all be discussed in terms of a (more sophisticated than current) analysis of what these future beings want and like, what their ethics and aesthetics consist of (and yes, these are complicated patterns to be found within their minds, not within some FOV), etc.

What I think is crazy is to reject all those answers and say you can't in principle be satisfied with any answer that could be different for a different civilization. I think that such dismissals are a mistake along the lines of asking for the final cause or "purpose" of the fact that rocks fall, and rejecting gravity as an insufficient answer because it's only an efficient cause.