https://github.com/jamesob/bips/blob/jamesob-23-02-opvault/bip-0345.mediawiki

My initial bias on hearing about OP_VAULT was 'meh, not only "yet another covenant op code" but also something trying to be ultra-specific (vaults only) instead of properly general'. But having spent a few hours studying it (neans: just understanding the basic idea!), I now have a very positive impression.

First, it now folds in CTV as part of the mechanism. CTV is a very pure and rigid implementation of 'constrain the spending transaction' and plays the role of building block in higher level protocols well. OP_VAULT is using it as a sub step and making generalised vaulting controls practical.

I feel like if there is a problem, it's that OP_VAULT is very flexible - tapleaf updating a la TLUV.