Thank you once again for the detailed comment 😊
Well as I also follow the Townhalls closely I heard the "Liquidity Pool" approach aswell. I kinda like the idea of those individual markets I mentioned in my post but those two concepts dont exclude each other. Maybe Region-Castles provide access to the big global market place and Liquidity Pools that are linked to Hive-Engine as you suggested and the Tract-Keeps act as some sort of smaller and individual exchange 🙂
For your storage concern I agree that the use-case of storages are yet tbd because of how dependent it is to the overall system. Yes one use-case will be that you unlock a larger idle-time but like you also said: what prevents the player from withdrawing to HE? I am no tech-savy guy so I dont know if it would be possible to mirror or implement the HE-exchange to the game so that resources still have to be stored, even when you put up sell-orders.
First use-case though will probably be to unlock higher-level buildings. I assume building upgrades costs will get higher and higher so at some point you have to upgrade your storage in order to have enough space for the costs