My biggest issue with all the investment in blockchain-derived technologies that aren't cryptocurrency related is that it's hard to apply proof-of-work systems to real world problems. How do you incentivize people for mining blocks? How do you ensure you have enough distributed computing power, so that a single actor can't take over the entire network? The company using a blockchain to track diamonds is a good example. Do I get diamonds for mining blocks? Then what's the point? Companies like Everledger claiming to run a "private blockchain" are only using the word as marketing bullshit, because that effectively becomes a centralized database/linked list.
Crpytocurrency/Money isn't the only way to incentive people. If a group of decentralized entities have a common interest that could be solved with a blockchain-type technology, it might make sense for them to throw computing power at it because it still creates value, even without a currency.
For the blockchain/proof-of-work concept to truly work, everyone should be offered some sort of incentive to participate in the network. It's the best way to ensure that a single actor can't gather enough computing power to take control of more than 50% of the network.
