Blockchain has been around as a technology for nearly two decades. If financial institutions thought it could help them you can bet they would be all-in on it by now. As it is, blockchain has no significant advantages over traditional financial ledger systems, so what incentive is there for them to use it.
It’s not something new or cutting edge any more, just waiting for a bright spark to discover the technology and put it to use.
Rather than resorting to that age-old cry of the cult member “do your own research!” can I respectfully suggest that if you’re aiming to change somebody’s mind, the onus is on you to provide the evidence, not on them. By all means take hours out of your day to search google and compile a list of things that you think will convince me. Me, personally, I have better things to do with my life.