Vault supports multiple worlds since version 1.2.24
This allows accounts to be addressed on a per-world basis, instead of only per-player.

Add support for multiple worlds to Gringotts core

Is this still being considered? We would like to use this in a multiworld environment but it does not work as expected. All items from all worlds will transact in the first vault created, regardless of world. MultiWorldMoney plugin keeps separate balances straight and money still works per world as designed. but users get startled to see empty vaults in other worlds, plus they can't carry items between worlds by design.

Currently there isn't much active development going on. Pull requests will still be accepted happily.

Vault doesn't support multiworld in a correct way for Gringotts.
I tried it and even if it does work it effectively breaks Gringotts' mechanics.

If I have some emeralds in a chest in world 1 and go to world 2 then back to world 1 my chest will be empty. The correct emerald amount will have been transferred back to my "/money" account, but there will be no emeralds in the chest.

Yeah, this isn't implemented in Gringotts yet.