In both high-end and low-end, I don’t think the iPhone apps are going to supplant in-line tuners. Maybe if someday we’ll be able to plug our guitars and basses into our iPhones, but that’s a pretty big if (right now). Then again, maybe someone will invent a bluetooth jack module that will stream guitar to the iPhone and let it tune that way.
P.S. Only four lines in the comment text box?