You presume that I presume. As other responses allude to, many of the grid-responsive actions that would be useful are on the scale of sub-second to minutes, a

You presume that I presume. As other responses allude to, many of the grid-responsive actions that would be useful are on the scale of sub-second to minutes, and happen day and night, eg when people may not be awake or near equipment to manage it, or just too fast or frequent to be reasonable to manage with a human in the loop. Auto-pausing the heating of your wash water or water tank for a minute or three when grid frequency falls will likely make no difference to you at all, but drops your grid demand (say) 2kWh ot 3kWh to help the grid quickly stabilise. More such responsive instant load shedding might have avoided the last couple of times that the GB grid had to shed several hundred thousand users entirely for a while. Those users definitely noticed. There are conversely many grid response actions that are on scales where it is reasonable (and maybe optimal) to have humans intervene manually to some degree, such as chosing to do laundry on sunny days when it can be solar powered and line dried at a day scale, and hotter 'maintenance' washes in summer (and not in winter) at a seasonal scale.