I kinda wondered about this forever as well. Then one day I was chilling in my local worker-owned cooperative bakery when the Brinks truck came by to do the bakery's cash pickup. Armed driver. Guard waiting next to the truck holding a long gun. Two guys (presumably armed) going into the business to get the cash and take it out to the truck. That's all pretty expensive!

Smaller family-owned businesses will just take cash to the bank - but it's super common for somebody to eventually surveil them long enough to rob them one day as they're transporting the cash to the bank.

It's pricey to handle cash!