I already owned the domain and have access to a server with more than enough resources, so it didn't have a downside to me.

Upside, I don't really have to worry about anyone else's federation choices. Undesirable content like loli/shouta stuff doesn't appear at all, because I'm basically the only user and don't subscribe to anywhere that exists so it doesn't federate to me anyway. My instance never lags because nobody but me uses it. Sometimes it misses comments through federation from overloaded instances, but it seems like the newer version of Lemmy has helped that greatly.