I had a very tasty Full English in Kington last year. When I tried to use Plastic to pay, the room fell silent and looked at me like I was a witch.
It happened elsewhere on Offa's Dyke, too. Luckily, I had a bit of cash, but it meant I ended up lugging a lot of heavy coins, which undid some of my ultra lightweight packing.
Some of my friends maintain it helps support local jobs, though I cant see the argument.