The tech costs more than conventional options upfront, but federal tax credits, new 120V models and strong savings have made them more appealing than ever.
Using gas to heat water is considerably cheaper than using resistive electric. Especially when the electric was historically provided by coal or gas anyway.
Burning gas to heat water into steam to turn a turbine to turn a generator to pump electricity to a resistive element inside a dishwasher is not nearly as efficient as just burning the gas inside a water heater and sending it to the dishwasher. The heat losses incurred while passing the water from a gas heater to the dishwasher are a tiny fraction of the losses incurred in the convoluted processes involved in traditional electrical generation.
Using gas to heat water is considerably cheaper than using resistive electric. Especially when the electric was historically provided by coal or gas anyway.
Burning gas to heat water into steam to turn a turbine to turn a generator to pump electricity to a resistive element inside a dishwasher is not nearly as efficient as just burning the gas inside a water heater and sending it to the dishwasher. The heat losses incurred while passing the water from a gas heater to the dishwasher are a tiny fraction of the losses incurred in the convoluted processes involved in traditional electrical generation.