one current only that mean you only depend on central bank of that money so that when loose it you will loose any thing it is so risky so that make more than one income soruce
Exactly. Too much power would be in the hands of a very few people so that won't be advisable for any society. Too much power causes corruption even for the most straight minded person.
If power is in one hand, then you wont be able to get right things. Reason is, you said, most straight forward and right person could even get corrupt. Power shouldnt be consigned in one hand rather must be distributed among many other hands for better running of system.