They are brilliant of course, particularly on topping rice as many a mujaddara-fan probably knows.
They are a bit of a pain to make so the CC decided to do some scientific tinkering around. He quickly realized that if you could have the onions lose moisture naturally before frying then the frying would be faster, and there'd be less splattering (both worthy goals to pursue.)
Naturally, that brought the humble refrigerator into light since modern refrigerators are dessicators. The fridge is a natural dehydrating agent since they dry out the main cavity to prevent growth of bacteria and mold. Sticking the onions sliced up thinly overnight in the refrigerator tends to dry them out which is not a good thing normally but it's brilliant for fried onions!