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Supply chain tracking is a fairly perfect match. An example in production usage today is https://simbachain.com/ and https://www.computerworld.com/article/3439843/how-pharma-wil... and a particularly interesting vaccine distribution database from IBM: https://www.ibm.com/blockchain/industries/vaccine-distributi... - or how about voting: An example in production usage today: https://www.govtech.com/products/utah-county-makes-history-w...
There is the obvious securities trading usages, but that may or may not qualify as speculative. Anyways, you could argue blockchain is a stupid tech for all those reasons and all the startups mentioned in these articles will fail - and fine, maybe you're right. Maybe postgres is better for all those jobs. But these are non-speculative use-cases. If they're the right fit for those problems -- well, I'm not running a crypto startup, so... But in the long expanse of history, I do believe trustless societies will eventually emerge.