Here is the link to BitVault creator's discussion on Optech. They were joined by @supertestnet to help explain the protocol.

I still don't feel like it answered any of my questions. Super pointed out that the vault starts counting down the CSV timelock as soon as you put your coins in it, and the necessity to cycle these coins or to use a pre-signed transaction construction.

As far as I know, pre-signed transaction vault schemes have existed for some time, but have generally not been used because they are brittle and unwieldy.