That sand also has a taste to it, and some dragons will develop a liking to it, and literally start eating it. In large amounts, it will kill them! Either that, or if you manage to get to a vet in time, you'll have a very large payment to make for a surgery to remove it.
I know it sais it's digestable, and the pet store sais it is, but it's really not. Remember, companies will sell anything people will buy, and do anything to get them to buy it, so they can make a buck, even if it's a lie. Companies don't generally care about the pet... just the money they can make off it. I use non adhesive shelf liner, and newspaper when taz is sick. You can even find some liners that have desert colors, and the cage will still look natural. Super easy to clean up too!