We use our propane for emergency heat also and it helps me sleep better at night knowing we are not dependent on grid power for heat (for a month or so, anyway). The problem for me with the cost comparison is the electricity is only 5-6 cents/kWh here and it is hard to beat that. I didn’t look at the price on the last propane delivery but it was probably around $3.50/gallon.
I get it for a lot less than that. But then, I use it for everything. Electricity is very expensive here.