And the places where it does make sense it makes sense only for running goats around in the PV sites to keep weeds down.
High population density countries also do farming and using every inch of land is essential. Demand for things sensitive to harsh sunlight (herbs, berries, and so on) or in places with long dry seasons means growing under shaded areas has advantages, and doubly so if you can extract energy while doing so. That’s also not exclusive to california.
I would argue countries like USA, Canada, Brazil, Australia are the outliers. Most of the world cannot afford to be as dismissive of land use optimisation as some US Midwestern farmers appear to be.