Making everything an app narrows the bandwidth between the user and the tool. Now everyone needs a phone, and you can't leave the scanner where it gets used, and you have to go through the generalized touch interface to get to the functionality instead of (and this is a valid UI) just picking up the scanner.
Reminds me of this excellent article by Bret Victor: http://worrydream.com/ABriefRantOnTheFutureOfInteractionDesi...
Making everything an app narrows the bandwidth between the user and the tool. Now everyone needs a phone, and you can't leave the scanner where it gets used, and you have to go through the generalized touch interface to get to the functionality instead of (and this is a valid UI) just picking up the scanner.