How much time is this really saving?
Assuming you use the slowest possible electronic payment method: the card swipe you save maybe 10 seconds? Using Apple Pay at the pump takes about 2s.
in my experience it takes longer for the pump to activate once I've completed payment authorization and selected a fuel grade. I don't know what the pumps do but sometimes that takes what seems like an eternity as the display resets, cycles through some self test then finally engages the pump motor to deliver fuel.
In either case you then stand (or sit if you go back in the car like I do) for about a minute for the tank to fill.
The time savings oppotunities in refueling an average passenger car just don't seem ripe for optimization. And it's not a particularly complex operation either (NJ, let people pump their own fuel). The ratio of time spent refueling to time spend driving is minuscule. 2 minutes to pull in, locate a pump, shut of engine, get out, authorize payment,open tank filler, select grade, fill tank, put nozzle away, clost tank filler. Then I drive for about 8-10 hours on that fuel. in minutes that's a 1:240 ratio fill:drive.