Developer Ryan McLeod recounts his work creating Gravity, an app that uses the iPhone 6s/6s Plus’s 3D Touch feature to turn the phone into a digital scale:
With the force values linearly correlated to weight, turning any force into a weight was going to be as simple as recording the force of known weights and creating a linear regression. It’d even be possible to use some statistics to predict how well the calibration went (there are many factors that can throw off a calibration). We opted to use coins for calibration, with a framework that made it easy to internationalize in the future.
Unsurprisingly, the app was rejected.
To make a long story short the final answer over the phone was that the concept of a scale app was not appropriate for the App Store.
We were—and still are—bummed to say the least, but we understand some of the reasons Apple might not be allowing scale apps at this time.
To McLeod’s credit, he takes the rejection pretty well, even noting that apps that bend Apple’s API for unexpected uses often aren’t accepted right away. But it is a shame, because it’s a clever implementation and Apple should be encouraging developers to think outside the box.
Really, what Apple needs is a small group within the App Store review team to flag apps that are pushing the envelope in smart, respectful ways; work with those apps’ developers; and present overall recommendations to App Store leadership—perhaps even reporting directly to Eddy Cue. Blanket rejections get you nowhere, and they increase the frustration of developers who are legitimately trying to do cool things that delight users—just as Apple aims to do.