Gary;
I have two A/C's with heat pumps. Is it a useful feature? For us, it's not only useful but very practical, and yes, it's just like a household AC/heat pump. Since we picked up our Grand Canyon last February, I have used one tank of propane and that has been mostly for cooking. We did have a few days where the temperature got below 35 and the furnace kicked on. That is an automatic feature so when you have the heat pump on and the temp drops below 35, the furnace comes on automatically. It only operates off of the main thermostat, not the one in the bed room. If you choose this option, make sure you do get the wall thermostat control, not the one with the control on the A/C. It works much better and you have more precise control. As far as an available option, talk to your dealer, I'm sure that they can get it for you. We got things in ours from Butch at RV's for Less that other dealers told us we couldn't get.
Don't feel bad about asking questions. That's what we're on this forum for is to get answers and share experiences.
John