You have no choice if using Crestron tstats. The problem with the hidden ones is reliability. I have a house with over 20 hidden sensors and depending on how deep they were installed in the wall, the temperature readings can vary by many degrees. We also have 4-5 that are bad and these now have to be dug out of the wall, replaced and wall repainted. I'm just glad I didn't have anything to do with their installation!