I never understood why SN didn't operate that way and kept the custodial wallet model. I think the UX was better that way.

Personally I don't mind to leave a few thousands sats on a custodial service, no need for bonds or other fancy trust methods. Most custodial services like Wallet of Satoshi rely simply on a typical trust model, their business depends on them not rugging their own clients, that's enough for me.