In my opinion the only good thing it does is to create copies of already existing communities, so basically people tend to follow one community or the other and it divides the people who could be active.
If you want to create a community that’s similar to one and for some reason you don’t want to be a part of it, find another name, if you can’t find another name, create your own instance. So if Lemmy is federating now we could have /c/worldnews, /c/world_news, and the same applies to every other instance that decides to do the same. In my opinion this only segregates people.
The same applies to uppercase letters, which Reddit uses but luckily Lemmy does not, imagine how many copies of a community could be created if you use both.
That precisely is one of the things I found it irrelevant for, what do you want to use a word separator for? It makes sense in names because there can be a million users, but with communities it’s not the same, we don’t need 5 communities with similar names.
Imagine this: /c/league_of_legends /c/leageof_legends /c/league_oflegends /c/leagueoflegends I just don’t see the point and I don’t think it makes it so much easier to read, since anyway most of the time you will be reading the display name, not the address.