Very simple. We get the option to have a universal hotbar that can be swapped to instead of having to make one per character. Particularly helpful for GMs in games with lots of characters with similar actions or players with a consistent play style across different sessions.
I would only want to see this if it was in addition to the per character quick action buttons. It would be great to be able to have certain actions available to all players, but it is also really valuable to have the players able to access actions from their character sheets without needing to open their character sheet every time.
It could be linked to the Gold/Platinum extended hotbar. In my head, you would open your character sheet and have a dropdown of Hotbar 1, 2, 3, etc. on the left side that you could name for ease of use.