Why would you not just always put it on the driver's side, since they're the most likely to be doing the refueling?
safest place is put it opposite of drivers side, because if you're out of gas on the side of the road and filling it up, you won't be standing right next to freeway traffic. Saab started this.
What happens when they sell the car in a country that drives on the other side of the road? They would have to move everything around.
My plug-in hybrid (Audi Q5) has the electric connector on the rear left (driver’s side) and the gasoline inlet on the rear right. I sure plug in way more than fill up.
The fuel side indicator is quite helpful to me.
And which side is the driver side? Surprise, it depends on the country. And a Japanese car manufacturer will move the driver controls to sell cars in USA/Continental Europe, but flipping everything else will cost more.
I've driven 2 models of an Italian brand, my previous car had the gas tank on the passenger side, and my current one has it on the driver side. I do wonder why they changed it.
There's also the issue of pulling to a small road side petrol station, having the fuel door on the passenger side means you don't have to be standing next to the busy road while refuelling.