I imagine you're referring to the importance of good solar conditions for the production of electricity and I agree that's vital. However these articles give false hope by matching peak solar production to the lowest possible consumption period which is always on the weekends with 70 degree weather. You have close to zero commercial machinery, zero need for climate control, zero lighting (people are either outside or use natural light).
I was talking about energy demand, sunday doesn't differ that much from monday, contrary to what you think. The time of day matters much more. You can verify this yourself by looking at CISOs demand graphs.
Why does this article give false hope? It just reports on a first time ever?