Would transactions necessarily be faster with a pull model? I’m thinking of situations where chain B is blocked or lagging in making transactions because it has to wait to pull and sync.
If you just changed the account owners, then you would have to wait some time for the changes to propagate. But transactions themselves should be instant, as you can always prove a slightly older state (though there would have to be some limit to this, so that key revocations can actually take effect)
It’s also worth noting that theoretically this works not just for EOAs, but also for any pure-function-controlled account, though that would have to be standardized.