In this case your nuance = pedantry. You have no custody over the funds that hold the value. That does not negate the use cases of Cashu, but it's important for users to understand as many think it is a way of using Bitcoin self-custodially.
Discussion
It is a method of custody solution that mitigates many of the problems of “fully custodial” solutions, including greater privacy, censorship resistance, reduced individual ruggability, bearer instrument qualities
That’s a pretty massive asterisk which applies to your “fully custodial” claim