I haven’t used it often, but the few times I have asked it very specific programming questions, it has usually been pretty good. For example, I am not very good with regex, but I can usually ask Copilot to create regex that does something like verifying a string matches a certain pattern, and it performs pretty well. I don’t use regex enough to spend a lot of time learning it, and I could easily find a few examples online that can be combined to make my answer, but Copilot is much quicker and easier for me. That said, I don’t think I would trust it past answering questions about how to implement a small code snippet.
You’re correct on the two thoughts you listed. Wishlisting also makes the game more visible before release. For example, highly wishlisted games appear in the “Popular Upcoming” section, along with some other spots. This increased visibility before launch then feeds into the two points you made. I believe games that are highly wishlisted before launch are also more likely to appear on the frontpage right after launch.