It makes sense that the court would want to avoid taking in almost $200mm in cash, then being on the hook for giving it back at some point.
If you put up cash collateral for a bond, that generally doesn't mean promising the surety you won't spend it. It means giving the surety a cashier's check and letting him hold the money. Thus the reference to the surety putting the cash somewhere it will accrue interest during the pendency of the appeal.