> The source can be attacked, the transmission infra can be attacked, the delivery point can be censored.
Who cares? One isolated field of solar represents a negligible amount of power at grid scale. Nobody is going to bother to go around attacking each individual field because the "ROI" of attacking a high-voltage transmission line (the kind that brings power from multiple thermal plants to a city) is so much higher.
You’re assuming such attacks cannot be automated. Which unfortunately they so often can.
Just take a look at the multiple fridge freezer attacks in the EU this year.
Attacks scale in the drone age, infrastructure left where nobody’s looking at it is a vulnerability. Solar stacked on an active farm has the benefit of having eyes on it constantly - detection, repair and recovery cycles are dramatically shortened.