Why is controlled load not enabled at midday

This page is currently a rant. As I find the answers to my questions, I'll update it.

Controlled load power circuits are a separate power circuit in many homes that is used to power hot water cylinders and other hardwired, power-hungry devices that don't need reliable 24/7 power. It is switched on at certain times but not during peak times, as to help the grid to supply all the other things that need power at those times.

Why then, isn't controlled load enabled around midday when it is sunny and the vast majority of the power on the grid comes from renewables, and most houses are consuming significantly less power than they would at night time? Why is it instead enabled at night time when power demand is as high if not higher than midday, and the grid is almost entirely powered by fossil fuels?

By enabling controlled load during the day, we can absorb more of the power that is generated from renewables, increasing the demand for them and moving that demand off fossil fuels. It also decreases the interval between periods when controlled load is enabled (usually only from midnight for ~6 hours), meaning that circuits that rely on this intermittent power get that power more often.

It would also often reduce the price of controlled load power. Renewables are so abundant and unused already that prices often get close to 0. On the other hand, there's a fundamental floor to the price at which you can dig coal up from the ground and burn it.

https://www.solarchoice.net.au/blog/how-do-i-use-electricity-throughout-the-day-the-load-curve/