Does this matter if my account is some random username about birds?
Like all people learn is "someone does in fact live at that address and they use this app"
Depends on what linking credentials you may have registered with. If they have a data leak, those details will be linked to your address in that way.
Seems pretty unlikely even with a data leak, that someone would go through the effort, but it's worth acknowledging as a vector.
Yah, this is what I do, however I think this is what GP is talking about when they say savvy (or maybe I'm flattering myself). Plenty of folks with their full details on their profile.
Maybe not, but I'd want to know beforehand either way. And looking through accounts near me suggests that a fair number of users add enough detail to make me think that they don't realize that their info is so public (selfies/profile pictures being the most problematic example imo).