I presume it's to make it harder to create sockpuppet accounts. Also, reaching those 500 points requires quite a bit of contribution, so there's a good chance

I presume it's to make it harder to create sockpuppet accounts. Also, reaching those 500 points requires quite a bit of contribution, so there's a good chance that you understand the rules by that time. I know the downvotes here can be annoying, but in comparison to Reddit, for example, it's very calm, probably in part due to that limit.