Yeah i get that they're all seeing similar but you'd still want to align this new demand with the output curve in some form of approximated pattern. Plus also prevent the sharp spike you'd get from everyone turning on their stuff at a coordinated hour. You're gonna have a bunch of stuff on timers all hit this at the same time. That makes life hard for the people balancing the grid's supply & demand.

Bit like in the UK they had issues with everyone watching popular TV shows and then turning on the kettle after in a perfectly syncronized timing across the country