Why do Lemmy instances have such obscure TLDs?

https://lemmy.world/post/2010270

Why do Lemmy instances have such obscure TLDs? - Lemmy.world

Whenever I come across a new lemmy instance, it most likely has some sort of obscure TLD (.world, .ml, .ee, .me, .social just to name a few). Why aren’t there more with more common TLDs?

Can a Lemmy instance be a subdomain?
Yes, sh.itjust.works is an example