What is the use of a private relay? It can make backups I guess (if you can export and import the data).
But what else?
I think the end point, for now, would be that you can have a relay-on-tor that runs on your phone.
Why? Because renting a VPS is a bridge too far for quite some users who’d be very much helped by having one more relay that can’t be blocked to themselves 🤔