By the term "Own Bank" I think it means a store of value but isn't all currency and assets have this already? Banks are known to be centralized but I think a decentralized bank is also possible. Dunno bout you but I think dollar is backed by something and anything that are legit is also like it. The backer of dollar can be literally banks and maybe the governments too?
Decentralized bank do exist, it's Bitcoin.
Dollar is backed by "trust", if all people in the world didn't trust Dollar anymore, Dollar will become worthless since the thing that backed Dollar is gone. After that banks will collapse since people will withdraw all of their money and they will not trust in government anymore.