rationalskepticism.org

Proofs are no more than shortcuts that allow reasoning, including other proofs, to start from somewhere other than axioms (on the grounds that the path from axioms to the result of the proof is known to exist). But any time you use a proof, you could just start from axioms instead. They're timesaving devices, and have the same metaphysical value as dishwashers or high-speed railways or corner stores, whatever that metaphysical value may be (I find "none" to be a satisfactory answer, but because it's metaphysics, YMMV).

Also, if we're to be able to compare the metaphysical value of various proofs, we'd need a measurement system and agreed units. I propose that the unit of measurement be "unicorn equivalents" (UE) where the rather lovely Euclid proof Cali gave above = 1UE. I eagerly await a rigorous calculation of the UE value of a proof of Pythagoras' Theorem.