Petroleum is a stable sunlight storage medium.

The sun is but a poor, corrupted pun on starlight. The reflecting pool of crude shimmers with thin-film interference like nebulae on the celestial expanse.

They will when supplies eventually dwindle. We were saved from peak oil only by the invention/cheapening of fracking followed by the advent of horizontal drilling and unlocking of oil in shales. It's unlikely any such windfall will occur again, and even if it does that merely kicks the can down the road.

All petroleum was created from ancient forests before the evolution of microorganisms that could decompose fiber, so the plant material was simply buried and gradually became petroleum. Above ground, evolution produced organisms which could break down fiber. My point being, that not only is petroleum very useful, it is exceptionally rare on a geological timeline (at least on this planet ). It's like a cosmic trust fund, and like most trust fund recipents, we utterly squandered it. We took all this free energy, burned it to power ai slop, and poisoned ourselves in the process. We should have been using that oil to push humans out of the gravity well to Titan where petroleum is abundant. But no, we wanted big cars, cheap electricity and single use utensils.

Edit: I was mistaken, confusing coal and petroleum. While petroleum comes from microscopic ocean life, coal forms from the remains of terrestrial plants.