We have a brand new ceramic tile backsplash in our kitchen and it will be exposed to steam and spray from the cooktop. (The tile we use is this one)

Q: Should we seal only the grout? Or both the grout and the tile?

I have read that if you don't have to seal the tile, don't because it can cause problems (what problems I don't quite know...)

Here are 3 sealers we could use. Do you recommend any of them or another product?
Miracle Sealants Spray on - seals the grout and tile
Miracle Sealants Impregnator liquid - seals the grout and tile (needs applicator sponge to apply).
Miracle Sealants Grout Sealer with brush - seals the grout only

Many thanks!