It’s still not earning you money to spend electricity because you still have to pay the transfer fee which is around 6 cents / kWh but it’s pretty damn cheap nevertheless, mostly because of the excess in wind energy.
Last winter because of a mistake it dropped down to negative 50 cents / kWh for few hours, averaging negative 20 cents for the entire day. People were literally earning money by spending electricity. Some were running electric heaters outside in the middle of the winter.
It’s not any different than most physical goods. Whatever you can’t sell before it goes bad, you have to pay someone to take off your hands using real resources (dumpsters, trucks, human labor).
Too much electricity in the system is harmful, and if nobody wants to buy it, then you have to pay someone to take it out of the system.