My prior is that Proof of Work is a solid basis for an (inefficient and tautological) form of digital scarcity, or even a public random number generator, but ne

My prior is that Proof of Work is a solid basis for an (inefficient and tautological) form of digital scarcity, or even a public random number generator, but nearly every crypto application outside of that seems to range from trivial, to mania, to downright fraud. Assuming I do want to understand the DeFi landscape (and willing to suspend my disbelief some amount to do so), where is a good place to begin?