I know of one chain here in Norway that does this, but only in a few of their larger stores. I believe you have to set up a card with them that is connected to your bank account. They have regular lines as well for the folks that don't do this.

I somewhat assume that when this becomes cheap enough, some version of it will be in all the places, probably in conjunction with something that weighs the cart or basket to see if it matches up to what you have scanned.