You don't clean it really. I mean, you sorta clean at it, but you never get those spaghetti sauce spatters out of the crevices. And any tile that doesn't get filled with grout, gets filled with dirt and yuck. Grout is used with tile for a reason, and it has nothing to do with decor. It's functional. And going without it is a very very bad idea. As is that tile in a kitchen. Or bath. And that doesn't leave too many locations where it would be appropriate.

Hmmm, nope, not really a chance I would want to use that for a backsplash - if you cook at all, you'll be at it with a toothbrush all the time trying to get it clean and it will never really get there. You are so very right to be concerned about cleaning it.

In our early parts of planning, I had someone at a design place show me a dimensional tile like that and he was so pleased, saying how wonderful it would look in kitchens. I stopped him dead when I asked if he included a cleaning service for the life of the kitchen because that's what it would require for me to put something in my kitchen was was so cleaning-unfriendly.