I think it's a joke, unless they are referring to setting them under a poured layer of epoxy like some bars do (or the reddit thread from other commenter). For tiling, it would be difficult to set them because they are so thin. The thinset would end up being at or above the level of your grout. Also cleaning grout from them while float grouting would probably not be very fun. Maybe you could get away with setting them straight onto a layer of grout which would be less durable. Also they are so small and they don't come on a mat so you'd pay a lot of labor for placing them in any sort of organized manner