Cash in an ATM is orders of magnitude safer than cash in a till, most significantly for the store staff as less cash invites fewer (traumatising, dangerous) robberies.
When I worked in a convenience store 20 years ago, we’d dump cash into a safe through a mail slot every time the cash in the till rose over a certain amount (the register computer would show a red bar with a message to this effect), and we’d routinely have to turn down requests for all but trivial amounts of cash back for this reason.
