A simpler design is an advantage in itself but it doesn’t cover all factors (e.g. pricing).

If your closest power plant burns fossil fuels, then there’s a big inefficiency at the power plant which still has the emissions followed by a considerable inefficiency in the transmission of electricity and still some heat loss from the wall to the food in converting electric back to heat. Electric heat is more efficient if you only measure from the wall to the food. It’s overall less efficient because you have fuel → heat → steam → turbine → electricity → transmission → heat conversion (lossy at every step), when you could simply have fuel → transmission → heat. And as a consequence electric is usually more costly. Exceptionally, some regions manipulate the energy pricing in order to make electric nearly as economical as gas.

So whether gas makes economical sense depends on where you are. The prices can also swing especially in Europe due to the Russian war. Thus having both options is ideal once you consider pricing (esp. fluctuating pricing). Having both options hedges against price swings and at the same time gives you the option to choose the kind of heat you need for what you’re preparing.

power outages

Some folks live out in the sticks and have frequent power losses. Every storm is likely to cause a power outage in some remote areas where the power lines are near trees. And because those communities are small, response time is slow. So the power can be out for days. Several times this happened to someone in my family when they had a cake in their electric oven. The cake would have been ruined had they not had the option to transfer the cake to a propane gas grill.