This is what I replied to nerd2ninja and I think it applies to your answer as well :
Those are more extreme, thus harder to mandate. And they don't affect the rest of the bitcoin UTXOs.
- If someone in some dictatorship is forced to use a custodian there, it doesn't affect others, and that guy can leave his country.
- Mandating a multi-sig would force the government to have lots of policies in place to be able to sign (or not) for every spend. A policy nightmare.
Whereas if we have vaults that can be mandated, you risk having siloed UTXOs on the network. It's also much easier to just have some kind of vault where the government gives itself a 72 hours to clawback a spend if they realize you're sending it to a Unacceptable Fringe Opinion Holder.
I see vaults as much more dangerous than what the governments can actually enforce right now with the protocol as it is.