I think the interest comes because multisig is hard. This basically allows you to have 2 single sig wallets and a safe bridge between them. This way you can spend when you need to but if they get comprised you can go dig out your keys from your backyard and actually use your worst-case scenario wallet.

This does use spks, not keys, so it is completely composable with multisig

This is a good point.

There is an important risk / benefit consideration to run at this point in the game.

As a non-developer the heuristic I use is "What is the absolute minimum that is required on the base protocol for Bitcoin to succeed and not degrade?"

There is a sentiment that is common with my developer friends who get excited and motivated to push ahead with 'making things'. This is totally admirable usually, but we are dealing with something a lot more grave here: the future of the world's money.

Every single new thing that is added to Bitcoin increases the attack surface as more and more focus comes on it. Vaults, OP_CTV, drivetrains, covenants, all of this stuff feels like we are touching things before the paint is dry.

Has enough time been given to consider the longterm risks here? Have essays and books and in-depth explorations been written on what covenants and vaults will mean 30+ years from now from a social, technical, political perspective? Could the top nefarious minds and governments in the world formulate an attack strategy (either technical or social) against this new thing that was not previously possible?

I know this seems a bit extreme, but if we assume it is the future of the world's money, every single decision matters.

I feel we only have so much time before Bitcoin ossifies and changes to base protocol become much slower or otherwise stop altogether. Therefore anything that is not absolutely mission critical needs to be skipped over or deferred to layer 2 by default, unless there is a very clear cut and overwhelming argument for it.

The steelman here is in the case that hyperbitcoinization takes place, and there are huge nation states and actors managing unimaginable amounts of wealth, do they need the added security of the vault function? Or is this something that really should be taken off-chain with private innovation in key management and multi-sig wallets etc?

Is it better to have an unforgiving and absolute austere base protocol or to have safety nets in place?

...Just my musings from a less technical and more social perspective, but at this point it is all far bigger than just code and a lot is at stake.

When you put it that way, it does feel like vaults are a lateral move security-wise.

Vaults appear more user friendly though. I can imagine my dad understanding and feeling comfortable with how a vault works. When I explain mutli-sig, I usually end up reaching for nuclear codes/keys as a metaphor.