>> Some of them even have functionality not available on the desktop web version- e.g. check deposit by photographing both sides of an endorsed check and it's done,

One of the slickest applications I've seen in a long time can be found at my Wells Fargo ATM.
The user can feed in up to 30 checks- handwritten or printed- at a time, facing up or down. The application scans them and decodes the amounts with uncanny accuracy.
The user verifies the scanned amounts and can override any errors.

If it can't decode the amount, it prompts for it.

I've never seen it fail to decode a handwritten check correctly and it reads most printed checks, but -oddly - it can't decode amounts on printed checks that I get occasionally from one of the largest financial institutions in the world.
The amounts on those checks look normal to me, so I suspect that there is some kind of hidden security mechanism at work.