I think a very legitimate, legal purpose of the technology is for the implementation of financial systems. How many billions of dollars of computers, networks, mainframes, and engineers are dedicate to running the financial system? Distributed ledgers are basically an abstraction for implementing financial systems. Think about them as C for the financial system, where the current financial system is assembly. The doesn't mean public, decentralized blockchains are the answer the any particular problem, but blockchain technology can be useful even if they exist mostly as private chains run by financial institutions.