I can still use Lemmy if the instance I would have used as my "home instance" ever went down.
Even if a public instance doesn't go down, all this extra load is making strange bugs surface that I don't encounter (I still have the live refresh bug everyone has, but not this one).
I have full control over my account.
If I ever want to get to customizing my UI later, I can.
Content I create originates on my instance, and I have full control over it. I can't stop other instances from caching what I post publicly, but this still gives me more data governance.
I can curate my "All" tab to only show stuff I actually want to see, instead of trying to figure out how to block communities (not sure if that's possible for regular users).
I get a custom domain which I think is pretty neat.