Granite Tiles for Bedding

I have seen many people use granite tiles to line the bottom of their chinchilla cages and I am interested in how it works.

Does this only work well for potty trained chinchillas?

I read that people get the tiles sealed in order to make clean up easier. Is that true and how do you do this in a safe way for the chinchilla?

Also, where do people get these tiles?

Are ceramic tiles better or worse to use?

Are there any other negatives or things I should know before switching to this method.

Thanks!