Not sure how this is an oxymoron, but I do see it as a bit convoluted. If one has a way of transferring a private key conveniently, one might just delegate the ownership of an UTXO. Maybe the Ark way is more cost efficient and flexible, as long as the ASP cooperates.

bitcoin

⚡ Using Ark as a backend of ecash, but self-custodial (and not as private)

isolabellart

SuperTestnet explores cool stuff.
Not sure how this is an oxymoron, but I do see it as a bit convoluted. If one has a way of transferring a private key conveniently, one might just delegate the ownership of an UTXO. Maybe the Ark way is more cost efficient and flexible, as long as the ASP cooperates.