Banks/financial institutions see the blockchain as a secure and excellent immutable transaction ledger. Crypto currency is just one of the many applications.
Also, they will not give the power that they have to the masses - allowing people to transact p2p and bypassing them in the process.
It's all about control.
The bankers never interesting with crypto. the blockchain gives a lot of advantages to the economic system which eliminated the 3rd party. They will only use blockchain to cut the maintenance cost and no more. But remember the bankers are not stupid person. They know what they will be doing with it.