The point is not to pay for stuff like electricity or gas, that you would pay anyway.
The point is you to pay for things, that you would not pay otherwise and that you are limited to, like pre-processed sausages, instant soups, soft drinks, floor cleaning products ... basically stuff you would live without and you would not buy if not given. Just to give extra spin of economy to go around products, that you would not do otherwise.
Gas and electricity are not there.