Because let’s say you’re Tom Hanks. And you get [email protected]
Well, what’s stopping someone else from adopting [email protected]?
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.
A difference between kbin (and mbin?) vs lemmy (and pyfedi) - the former would show the entire name, including instance. If instance was not included, it was because it was local (so you could assume ‘@kbin.social’)
On lemmy/pyfedi the name shows up alone - though you can hover over and see the instance name. But at a glance I can see how someone could get confused. Not the best UX IMHO.