Never seen a peel and stick mosaic.

I use peel and stick vinyl for closet flooring in various places - cheap, easy to clean, and the expense of using a better quality flooring there does not seem to be worth it. The last batch I got was a tolerably well-done "wood-look" and had the added advantage of not stinking like the old ones (10 years or more ago) I had last used.

I would not put them in a hot/steamy/wet area - that would be best served by a more traditional mortar tile attachment, or (what my house growing up had) a sheet of stainless steel (it was easy to clean, fireproof, and somewhat predated the popularity of an "industrial look." It's not for everyone.)

Upon searching for "peel and stick mosaic" I see that the probable maker claims they are suited to the use, but I'd still take that claim with a heathy dose of salt, personally. As a confirmed pessimist I'd also take a scrap piece and try to set fire to it. Ceramic or glass is "fireproof" not merely "heat resistant." Likewise, consider the less-glowing reviews as well as the glowing ones.