I have only heard of one good use-case and I have been in fintech for the past 6 years. Swift GPI allows banks to credit the receiving parties' account in 10 minutes rather than overnight. It's an example where the existing party (swift) already had accumulated all the trust necessary and the consolidated ledgers were updated overnight. Swift GPI allows a bank to track any inbound payments and recognize it to clients…
SWIFT has been playing with blockchain for years, always backing off. They had a partnership with Ripple once, some hackatons, a lab dedicated to blockchain. Former CEO even bragged about making bitcoin transactions himself.
There was one corner use case around GPI and R3 Corda announced in 2019, but I doubt it ever was used in production.