Some old school systems had a lot of value.
But the mechanical pumps were obsoleted when self serve gas came in and they wanted a single clerk to be able to monitor all the pumps from inside, also pay at the pump with credit cards.
Realistically is would not take a huge gen set to power the typical convenience store / gas station and it would give them a real competitive advantage vs those that didn’t have it.
I remember seeing the manual pump handle in a gas pump once - the station owner opened the pump’s case to work on something inside the pump. Lo and behold, there was the back-up manual pump handle tucked away inside the casework.
I agree that a convenience store or service station with a generator would be in high cotton during an emergency.