The UTH doesn't do anything for ambient temps but it does provide belly heat which is used for digestion. I would recommend picking up an infrared temp gun, it can accurately measure surface temps of the substrate. A digital probe is good for the ambient temps. I'm also new to the BP world and have been researching care info about them. I had the same thoughts about the slate tile as you it works very well for Leopard Geckos and distributes heat well with the UTH. Maybe it isn't widely used because it doesn't hold humidity though.