I can only speak for myself and my club , Bank deposits are optional and not expected or required , I've never kicked anyone out of the club that has deposited credits into our account , And if I did I would refund the credits to that person .
As far as how the credits are used , We have a thread in the club forum that has every transaction , So everyone knows where the money goes and how it is spent . If someone has a problem with that then I would refund their credits , Or they should not donate credits to the bank .
We have has a bank for well over a year now , beginning in July 2016 and no problems . With the exception of rogue entrants into bank deposit tournaments , Bank deposit tournaments are suppose to be for champion tier only, however sometimes the creator of said tournament makes a mistake and accidentally makes it for all tier levels .Otherwise we have no problems .
We have 12,000 credits in our bank account at the moment , Most of the credits are used for club tournaments , I do send out CC passes for the clash to members who want to play and need them .