I have an extremely low opinion of blockchain/crypto, but in the interest of fairness, I did read an FT piece a few months ago about how banks are apparently actually using the blockchain for currency trading: "HSBC and Wells Fargo are cutting out a key part of the currency market’s infrastructure from some trades after the two banks agreed to settle transactions directly on blockchain technology. From Monday, they w…
That sounds to me like someone used excitement about "blockchain" as an excuse to upgrade a two-decades old system to something a bit more modern. It looks like it's a private blockchain shared between two (at the moment) institutions, which means it's probably being used basically as an append-only log.
In hindsight, the Big Data hype wave was really just a good excuse to bring in a wider set of analytics tools than Excel, Access and inflexible, IT-administered databases.