You drove and pulled up to the gas station to fill your gas tank. You exited your vehicle, opened your gas tank cover, grabbed and put the dispenser nozzle in. You also had to pay at some point.
How can you forget that the hose is still connected to your car when you drive off?
Probably a combination of better theft deterance, and peoples expectations for convenience. In NZ there’s a mix of some stations that let you fill before paying, and some that don’t. When some stations first started operating on the pay first model it felt really inconvenient and annoying, so I guess it’s also a way to compete with other stations apart from price. Some stations will probably eat the cost of theft if it results in better sales.
Also probably that there’s other types of crime that are more popular in Europe. Maybe because registering a vehicle is more of a hassle in many countries there than in many states in the USA? So criminals are less inclined to do crimes that will get thier vehicle wanted from cctv footage, unless they can easily steal some plates from another vehicle.