I can't speak for everyone but it seems to me one does gain something. If you didn't, why bother at all? Whatever you gain may be small and it probably doesn't

I can't speak for everyone but it seems to me one does gain something. If you didn't, why bother at all? Whatever you gain may be small and it probably doesn't have any monetary value but there should be some extrinsic motivation to answer. There are plenty of alternative uses of your time. Thus, my greater point is: when you have decided to answer, you should give the best answer you can reasonably give in the time you want to use. It wont hurt you and will improve the world a little bit.