Thanks for the information. I recall seeing them when I was a kid (1970s and 1980s).
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.