Because let’s say you’re Tom Hanks. And you get TomHanks@Lemmy.World
Well, what’s stopping someone else from adopting TomHanks@Lemm.ee?
And some platforms minimize the text size of platform, or hide it entirely. So you just might see TomHanks, and think it’s him. But it’s actually a 7 year old Chinese boy with a broken leg in Arizona.
Because anyone can grab the same name, on a different platform.
We decided to not host any sort of Buy-Sell-Trade community on our hobby instance for this reason. It’s a small community so a lot of people know usernames of people they know and can trust. It’s very easy for a scammer to use someone’s username and say “I’ll sell you that thing! Send me $150!”.