They have cash-handling processes similar to a casino, but again, they have much less than a casino or bank to take.
Employee theft is a much bigger problem than robbery, because you can imagine who works at them, but even then, it's hard to get away with.
You'd be much better off robbing a busy gas station or the like.
This is lazy thinking.
Any business dealing in cash and desirable inventory will have theft problems. In fact, the inventory doesn’t even have to be desirable. Consider office supply theft. It’s rampant; a cost of business to some degree. And part of the motivation is simply the righting of perceived wrongs.
Employees will always take from their employers, in every industry and at every class level. In industries where there are no “things” to take, the employees simply take back their time.