I recently had to clean a showroom floor which was dirty however I noticed it was specially dirty round the edges.. Apparently it had been sprayed with similar grout protector and left!
Funnily enough yes I have but mainly used so many as the tiles are 800's and they're having plinth lights across the floor which will illuminate the slightest of lips so just being over carefull 😉
The stuff in an aerosol is perhaps handy for tiny areas but you don't get much product for your money, a proportion of the contents are the propellant.
I have recommended this to plenty of customers, I advise them to spray it into the lid and apply it with a paintbrush to the grout lines, saves on having buff tiles and it lasts longer
Best way to use ltp grout sealer is to spray on leave a few minutes then a quick buff with microfiber cloth especially high gloss tiles.
Biggest mistake made is holding can to close to joints, should get around 600 linear meters to the aerosol if instructions are followed, also they do a liquid version in 1ltr bottles for large area's.