Basically the first bullet point above was meant to help with war rooms when lots of players need to pull from pot storage all at once. TBH I don't actually know how big towns manage this, or do people just wait their turn to pull stuff out?
People wait their turns in pre-warp, but if it's a clutch moment (like when you die in war and need to warp back quick) usually there's barrels / chests / pre-filled shulkers to grab. Tbh, apart from people being way too slow sometimes and hogging the chest, it's not that big of a deal.
Personally what I'd use two different VS systems for, is to manage the amount of pots/steak/pearls available in the war room VS system. Would be nice to be able to do something like "move 2k pearls to system1", instead of needing to have chests full with shulkers of pearls in the owner storage to prevent someone from taking 50k pearls at once.
Perhaps that could be achieved with some kind of rationing system (people can take X amount per Y time), or some kind of reserve (only X/Y goods can be taken by non-owners).
Actually now that I talk about other solutions, two different VS systems doesn't really seem needed. For my own room, except for maybe heads/blood, and possibly shulkers, a personal VS system doesn't seem needed, and in fact might have negative effects, in so far that if someone has that many shulkers that they can no longer fit them in chests in their room and need a VS for themselves, I'd rather they just donate their surplus shulkers to the town storage.