Banks were never going to use the ripple currency they were always only interested in the blockchain. Using a speculative asset for transactions makes zero sense to a risk averse bank. The reality is that ripple is a speculative asset and has no real use other than minimal amounts to prevent spam attacks on the network.
Apologies if this is a newbie question but isn't Ethereum very similar to ripple? Ethereum is the technology/network adopted by some banks and corporations but Ether, the currency, is not?