My understanding is tha some commercial/industrial users will get a highly variable tariff. This may be cheaper much of the time, but can get ridiculously expensive at times of high demand.
The difference is that a bitcoin farmer can shut down at those expensive times, but a home user still needs to heat/cool their house, run their fridge etc, so the savings cancel out. Because of this, averaging the costs works out easier/better for most home consumers
I have real time pricing from my utility. It works out well because we charge 2 electric cars overnight for a fraction of what they would cost to charge at the standard fixed kilowatt-hour rate. My house is heated by natural gas; I don't think the savings would be there if I also was heating my house with electricity as I live in the midwest, where it gets cold as fuck for the winter.