Huh? These drug dealers had $88,000 of drug money hidden in their car, not in their bank.
They had $88,000 in cash. At the time it was seized it was unknown and irrelevant whether they were "drug dealers" or if this was "drug money". It was seized because it was "too much cash".
It's not too hard to figure out that the bureaucrats have an interest in making people conduct as much of their financial affairs as possible through banks because it makes the details of those affairs easily available to them. The don't want people conducting any substantial amount of their financial affairs in cash, and will do everything they can to discourage it.