Oh no. Not only is it barely a claim on a treasury position, it can be frozen or confiscated unilaterally by the stablecoin issuer. It’s not self custody of anything!
Its not that interesting. The models you're interacting with are text generation models. That is they take the context of what you provide it and tries to predict what the text that would come after would look like.
They aren't search engines and they make stuff up all the time
If we are taking “self custody” to mean literally possession of the USD in a personal digital wallet, I believe it is.
In the same way cash (dollar bills or coins) is a way to take physical custody of money rather than letting the bank control it.
As well as physical custody of precious metals in the form of coins or bars would be considered “self custody” compared to paper gold or silver.