For me, the main issue is about having to refill 40 lb propane tanks that weigh 72 lbs full. CheapHeat Hybrid Heating System from RV Comfort Systems is an add-on to the existing furnace that lets me run the furnace on 120V AC with the flip of a switch. The only reason to flip it over to propane is to test it once a year. I've had it for about 5 years and love it. And of course, if your electric is included in the price of the site, it costs you nothing.
If you stay in one place all the time, you may be able to have a large propane tank placed on your site and have the company come by to keep it filled. Some parks will allow that. But keep in mind that propane prices can fluctuate pretty wildly. Back around 2013/2014 prices popped up to $5 or $6 per gallon in the Colorado mountains. Electricity pricing is much more stable.