What you are not taking into account is that the energy they will be using would be lost at 100%
and possible even cause damage to the grid, if not used.
As we build out solar and wind, (mostly solar) there will be periods where the surplus is more than the system can handle.
This has already happened in California,
Prognosis negative: How California is dealing with below-zero power market prices
Having the ability to store the energy that would be lost as heat in the grid, is very important,
and batteries are not up to the task for the volume and duration of storage needed.
Thankfully Nature has evolved a very high density energy storage medium, hydrocarbons.
Consider a future where surplus solar electricity is stored as natural gas, to be used in a combined cycle power plant
when the sun is not shinning. Or homeowners are given fuel credits for their surplus electricity,
and the fuel is carbon neutral. Put up extra panels, and they can supply fuel for your car!