It kinda started with the bazaar, but the current living is just as relevant.
The NPC outside the tower require both gold and a collectible as payment. But only the gold is accessible to me at all times. If i do not have enough of the collectible on hand, i have to waypoint to a bank or crafting station, withdraw as many of the collectible as i need, and waypoint back to make the exchange.
Given that said collectible goes straight into our bank when we hit “deposit all”, unless we remember to move it into a invisible bag first time we get one, it would be very convenient to be able to use it without having to retrieve it first.