I've been looking for an alternative to Simple for a while now and haven't heard of this until now. However, I don't think this is my answer. It's slightly confusing to me what Google is offering here since it appears that BankMobile already has apps and accounts?
In either case, Google being tied to this doesn't give me much confidence. "Google will provide the front-end, intuitive user experience." Ah yes because Gmail is the pinnacle of UX. I haven't used any Google services in years (other than YouTube I suppose) but the last I remember of them were not impressive.