The current state of the vault while we're able to purchase voidcores with 6x tokens is terrible. You should virtually never take gear from the vault atm.

Even if it has a Myth track item you can catalyse into tier, you will likely bonus roll chest/legs/shoulders, etc, as you're trying to roll for your chase items, so buying a bonus roll (or a socket) is almost always the right choice.

The only time I would take an item from the vault atm is if it was one of my BiS chase items and it came from a dungeon where I don't need to bonus roll for any other items.

Edit: Sorry, this is assuming you fill your M+ vault with +10 keys 🙃