Each financial institutions has their own budget, plans and how they want to run their financial economy successfully, we don't have to persuade any into choosing any means they have adopted to use as their own medium of payment until their eyes open to see some things unclear to their visions to know the difference between what they are using now and that which they are missing out, maybe in some cases, we should not always think about our own self alone, but other things tide to making decisions by these institutions.
Much depends on economic sense. Cryptocurrencies offer mostly low transaction fees and minimal barriers to cross-border payments. This is a huge advantage, so anyone who can count money will take advantage of it. Large institutions know how to count money