Because currently, it seems like the only thing it’s recording are downvotes. Meanwhile upvotes are completely ignored, leading to pretty much every profile I see having a negative reputation.
Also, I have a very fragile ego and my -6 reputation hurts a bit.
Not exactly - it’s technically a “favorite” button. Since I learned exactly what you typed out, I’ve been using it as a way to save posts I want to read later. However it is correct that it does nothing for reputation.
It does, AFAIK affect the post ranking i.e. order of posts. So it’s got that going for it - which is nice.