#1750 obozzo doesn’t do anything to save money so my best guess is:
He knows we are headed for a NG shortage or rolling brown/black outs and he’s installed a generator to run his complex.
He’s an idiot for picking propane then. Less energy density than diesel, giant surface mounted FAE, little top cylinder lubrication. It’s also going to be a LOT easier to get a refill or put a few gallons in with that as opposed to a room temperature liquid fuel.
In a SHTF scenario your propane supplied equipment is probably at its end of use when that tank empties (unless you happen to have a nearby sealed sewage pond you can cap and draw gas from). With most of the other liquid fuels you can gain additional use with added quantities garnered over time. In some instances you could actually make it, particularly with diesel or alcohol capable engines.