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.
You’re missing the point. You can have Tom.Hanks@twitter.com but you can’t have Tom_Hanks@othertwitter.com
So when you come to the fediverse, instead of searching for Tom_Hanks@tomhanks.com, you just search for Tom_Hanks, and the fediverse will know that defaults to the account Tom_Hanks. Which is the same account on Lemmy, the same account on Peertube, the same account on pixelfed.
Because it’s all Tom_Hanks.
Except Tom@TomHanks.com will come up first because they will surely have the most fooloerrs.