Houses don't tend to have consistent electricity usage. Think of the electricity usage for a suburb. Chances are it's almost 0 most days. People get home and turn on the stove, the washer, the TV, etc. Big demand spikes at certain times of day, low demand for the rest
Commercial usage goes the opposite direction. Higher during the day when stores and offices are open, lower overnight
Industrial usages tend to be more consistent, but constant. Factories don't shut down overnight, but they have high constant requirements
But as a power company you are supplying all of this. You have to supply a consistent load that satisfies all of these usecases. It's all one grid after all, outside of some very unusual cases
And if you oversupply too much you break the grid. If you undersupply then stuff that relies on you shuts down and breaks
It's very much a goldilocks problem, which is non-trivial to optimize or automate