You can but they are more prone to flexing, I'd bond a 4mm hardisheet to the reqd area, a coat of primer for your 2 coats of waterproofing ( cromellins is a great
Product, then use an ultraflex adhesive, davco or 2 pack, smaller tiles will allow more movement , however you can buy effect waterproof tile backings
But yeh they look ****e imho