Here it works where I am. I pump, I end pumping, I go inside and I pay.
Pay-after-you-pump disappeared from the US sometime in the '80s: it was still here when we left in 1984, but was pretty much gone by the time we returned in 1988. Paying cash before you pump an unknown quantity of gas is a pain in the ass as a result. Even if you just want $20 worth of gas and know it's not going to be a fill-up, you're still wasting time going inside unless you happen to need something more than just gas (and if I need to go inside for something, I do that after filling up and moving to a parking space to free up the pump for someone else).