It's exceedingly useful that you can run all your gas appliances at full power at the same time without needing the ridiculous amount of copper or aluminum it takes to carry the same load in electric form, and do all that while the power is out, because the power is up on poles and the gas pipe is in the ground.
Now imagine trying to replace the redundancy by ups or generator. The amount of copper, electronics, and batteries needed to make a ups that can run your furnace or ac and your stove and hot water is just ridiculous. Most people simply won't have it. Wildly impractical luxury.
It's kind of ridiculous to require $billion chip fab infrastructure to make heat, and have your stove be this delicate piece of complex electronics and the burners are all these fixed little circles that don't heat pans evenly because it costs more money to make the fancy burners large enough to cover a whole pan.
Meanwhile a gas stove is just a couple chunks of dead metal and almost no moving parts and doesn't even need electricity let alone any electronics. That is a huge practicality and robustness win.
And heats pans more evenly because the flame does not have this weird artficially sharp 0%/100% border. Even a small simmer burner heats a large pan more evenly because although there is a hotter spot in the center, the flame still spreads out and travels along the pan and up the sides no matter what size it is. It doesn't care what size the pot or pan is, and also doesn't care what the pan is made out of. That is huge.
Electronics and heat are not natural together. It's a constant fight to try to prevent heat from killing elctronics. Every day that one of the thousands of electronic parts of an inductive range sittng above a hot oven and below a hot pan doesn't fail is a lucky day. It's not just reliable by default by just being simple.
It's not a slam dunk all-upsides trade-off.
If the home owner has natural gas? They should could get a natural gas generator, that way they have a continuous supply of fuel if the grid fails.
Grid and gas failure? That happens only after a significant event, like a major earthquake. Not much you can do about those sorts of events. ( The person lives in Ohio… so not as much concern. )
Cost-wise? They would be better with a dual fuel system for heating. They live in Ohio, they probably have AC so moving to dual fuel when the AC system needs to be replaced is the smarter option.
So you need backup electricity either way. And in the case of a furnace it's still a significant draw due to fans and/or pumps so to get multi-day resilience you need a big battery. Less than if it was a heatpump, sure, but this battery and inverter system will use all the same amount of electronics either way.
No one likes steam these days because it's old and difficult to install correctly or modify later, but steam has some really cool features.
First, it doesn't require a pump to circulate. That means both the mechanical reliability of not having the electric motor and rotating water seal, or any moving part at all(1), but also you don't need any electricity.
It doesn't even need the usual low voltage circuit for the thermostat and gas valve. These are not common but also not new, there are millivolt systems where the thermostat & gas valve run only on the electricity generated by the thermocouple on the pilot.
It means that when ice has taken down all the power lines in a region, and blocked all the roads for repair crews to fix them at the same time, your heat stays fully working. No air blower, no water pump, not even 24v for the thermostat, and not by dint of having a ups which is just more stuff to fail.
Same goes for the hot water and the stove but that's more about gas than steam.
There is no getting around the huge efficiency of heat pumps of course. It just still kills me that we are accepting it as normal to require TSMC and ASML $billion chip fab infrastructure to make heat. But I guess you could say the same about leds and light so whatever I'm not saying we shouldn't use heat pumps.
(1) there is a moving part in the vent that opens and closes on each radiator, but that is a quality of life and longevity thing. If the vent fails to close or seal, the radiator still works, you still have heat, it just makes a hissing noise and consumes more fresh water which corrodes the boiler faster so it may leak in 5-10 years instead of 20-never.
It does work well, and when it gets cold in the winter and the efficiency of the heat pump drops, he burns wood. But honestly the system is a jungle of pipes and valves, and the guys who did the heat pump installation were unable to wrap their heads around it. Luckily my father is a handy guy so he was able to do it himself.
But I'm thinking if one were to do something like this from scratch, without the history of the existing boiler already being there and installed, I wouldn't bother with it. Just have a few good old school wood stoves with significant thermal mass (masonry heater or whatever you call them in the US) in the house that you can use to provide extra heat when it's cold, and as backup in case there's an electricity outage.
This is in Europe, might be different on the other side of the pond.
Perhaps look into "air to water" heat pumps.
* https://www.bryant.com/en/ca/products/heat-pumps/33nm3/
* https://www.arcticheatpumps.com/high-temperature-heat-pump.h...
Then run a wee bit hot water through your cast iron rads for the look of the thing.
Yes, the heat pump will take an efficiency hit for using radiators rather than underfloor heating. I'd say that's just part of the cost of living in an old house.
But if you insist, I believe there are high-temp heat pumps available that will make better use of old-style radiators.