Why don't TC makers use the Truma Combi units?

Personally I don't have much interest for this. I rarely am plugged in. I'd prefer a diesel furnace and water heater. For now I'm planning on a solar hot water system supplemented by solar electric for summer time use. That will cut my summertime propane use to cooling only.

I also don't mind the sound of my propane furnace. It doesn't bother me at all. If I was to change anything it would be the two way fridge for DC only Danfoss type compressor as I have plenty of solar electric.