geologists could also tell you where the best rocks are.

FTFY

If we put it like that, every other energy source on earth begins that way and adds at least one conversion step.

… except for fusion of course.

Solar cells, technically.

boiling water systems have a thermal efficiency of ~40% Solar cells are closer to 45% efficient

This is just plain false.

There is no theoretical size limit to unobserved quantum systems, although it is practically hard to achieve large ones.

the largest ones we’ve managed are over 100 atoms. https://www.livescience.com/19268-quantum-double-slit-experiment-largest-molecules.html

Yeah its about quantum systems interacting, not sentient beings watching.

still pretty mystical though in my book!