Robbing a bank is not a great risk reward. If you can scope out a cash transfer maybe. Or tunnel into a vault. But the banks make sure the authorities go hard against anything that causes them to lose money.
Holding up a bank from the teller, you could get a few thousand dollars, that's it. The numbers on the bills are recorded and if you spend them they will pop up on their computers as they are deposited in banks again, and they throw dye packs in a lot of the money, and trackers. Plus all the cameras, they can id people on their gait.