Just like the cell phone, cryptotech is slowly integrating into our every day lives. Now that even the banks are starting to look at it, I think it won't be too long until wide spread adoption begins. The so called "killer app" will actually just be when the first major bank allows direct trade of bitcoins<->fiat. It has to happen because of game theory!
I'm not 100% with this, but I've been wondering whether the big financial institution that moves first might be the big payment processors (VISA/Mastercard/Unionpay). They have less to lose from adopting bitcoin directly, and they will know that less well informed consumers will trust their brand.
And speaking of brand trust, think about the developing situation with capital controls around the world; this does affect brand perception for these companies, because their product cannot be used in a growing number of nations. They would be wise to begin innovating some kind of hardware wallet or bitcoin denominated card payment system, otherwise there is a risk that some critical mass of consumers begin to (however irrationally) associate the failure of fiat based cards with the payment processors themselves. "This VISA card crap is useless round here, cash and bitcoin seem to be the thing"