I've never heard of the mats, but I'd use the tile setting spray adhesive without worry especially for a backsplash. You can grout the same day and in my business, the second trip saved is the difference between making money and not.

The adhesives will bleed through porous stones like marble or crackle tile and permanently discolor them.

Linda, do you have any links to substantiate your claim? I can't find any. Thanks.