I had an `Element' brand 32" flatscreen that I installed initially, and it also had a 'Wall Wart' style transformer that outputted 12V to the TV. Since the 12V outlet is right next to the TV I was going to run it off 12V...... But ended up getting a better sounding new TV and the other is in one of the bedrooms. The new TV was 110v only.
We dont have an inverter in the coach, so the 12V conversion was so Grandma V and Grandson would have TV while on the road. I am blessed that he has YET to even want it on when we go anywhere!!!
I suppose you could do the DC-DC and have that extra level of protection. With the 32" I put in costing me $80, I am not going to spend a lot of time and energy in protection circuits. BUT... I am talking the 'Best Buy' quality. If you go out and get one of the RV TV's for several hundred, Sure!!