I am not an electrician. Why bother to have 220 anything? Why were the pump jacks in Texas 660 then? Why was all the electric baseboard I tore out of my house in Maine 220? Just run normal wiring and be done with it.
My uneducated guess is that the greater power requires larger wire diameter. Allowing for loads that are more then 1500 watts on a circuit. In houses that have been wired poorly, like 14 wire, this can cause some heating issues with the wires and outlets as I found. And this house has 12 wire. I was also told that power balance is important at the panel. 220 pulls from both legs of the incoming power and balances out large loads better for better efficiency. Why do "experts" say you will spend less money with a 220 water pump over a 110 water pump for the same work done?
But what do I know?
We are way off topic....
just a summary, you are correct with ampacity and wire sizing. But the big thing with comparision of 220 and 110 is amp draw on a 110 pump vs a 220. You spoke earlier of 3 phase, this is an entire new can of worms. We could go on for days. An easy analogy and i will end it with this, Just say an electric stove will pull 25 amps. You can install 220 with a 30 amp breaker and run 10 gauge wire, now if that was 110 you would need double the ampacity say a 60 amp breaker and maybe get away with 4 gauge wire, ever play with 4 gauge wire? Guess how much a roll of that costs
Then you get into unbalanced loads and ...and ..... and I could go on. Folks go to school for years to fully understand this nonsense
Keep it simple and stick with how its been done for years, thier is a reason electricians do things the way we do. Back to topic, Propane is great for gas grills and buddy heaters for ice fishing. I guess its convienent for lanterns too but no way for home heating.