If you do decide to apply a product, take care that it does not leave the surface slippery when wet.
I used a silicon based product to seal (with a shine) the tiles on my terrace. It was recommended by Pinturas Andalucía. It never dried completely, although not wet to the touch, but it was 'sticky' which meant dust adhered to the tiles, especially in the 'non slip' indentations, which was impossible to remove with conventional methods
I had representatives from Pinturas Andalucía and the sealant manufacturer at my place several times, and despite all the removal products they supplied (free) I finally had to buy a power washer to remove, 100%, of the sealant. Quite a time consuming job with 100m2 of terrace. It is now sealant free, albeit dull !