Since the EU capped credit card fees last year, most stores I go to already adopted credit card payments. I've used them at Aldi, Lidl, Rewe, Kaufland, DM, Rossmann, Thalia, Hornbach, IKEA, Media Markt, Saturn, … (Though sometimes cashiers are extremely surprised when I use contactless payment. They didn't even know they had it. Obviously it's not widely used, yet.)
Contactless payment already is extremely convenient. But I'm looking forward to slimming my wallet a bit more.
My 20-month year old does … Although she doesn't always get all the vowels right.