Electric resistance heat should be reserved for days when you ARE connected to shore power or for very short warm ups in the morning for all of the above reasons.
One thing that is happening in the RV industry is some units are dropping propane altogether. This is a very controversial move, but most campers use shore power so electric heating is plausible. Yes, heating water with electricity is slower. I don't see cooking with propane as being a huge advantage, especially with microwaves, countertop convection ovens and induction cook tops/plates.
The benefits are space, weight and cost ! As solar and LiFePO4 batteries become more cost effective, those costs will be smaller drawbacks.
I am surprised at how few people have switched to residential mini-split heat pumps.
