I find this very unprofessional when people can choose any set of characters for their names. This makes no fun when you try to tag them (using the @ symbol), or search them in the site.
It looks very bad also. Think of a site that looks like a soup of:
奇怪的用户名 اسم مستخدم غريب ထူးဆန်းသောအသုံးပြုသူအမည် విచిత్రమైన వినియోగదారు పేరు
Also keep in mind, some of them can have slurs and curse words, and no one will ever know. Because what are the chances that a moderator knows "Telugu language" (can you spot which one is it, really?)
Anyway, I find this unprofessional and not very nice. Also - no, I can’t be asked to "copy" their name in order to tag them, or search, because you have the feature of auto-complete and I want to use it, and copying&pasting makes this feature useless.