As long as gas is used to produce electricity the energy delivery systems are not independent.
In a home the two systems generally serve different purposes so I am not sure the value of having both is as high as you suggest. My gas furnace/hot water heater won’t turn on, for good reason, without electricity. The only thing that works when the power is out is my stove top (not the oven) if I manually ignite it. They would work if I used a generator but that is third supply and it shouldn’t be lost that the output of the generator is electricity. That generator could itself be powered by natural gas but that is not common.
In a home the two systems generally serve different purposes so I am not sure the value of having both is as high as you suggest. My gas furnace/hot water heater won’t turn on, for good reason, without electricity. The only thing that works when the power is out is my stove top (not the oven) if I manually ignite it. They would work if I used a generator but that is third supply and it shouldn’t be lost that the output of the generator is electricity. That generator could itself be powered by natural gas but that is not common.