The strength of pinch-to-zoom as a UI interaction is that it is direct manipulation. It has less to do with accuracy. Two-finger tap is a "computer command" to do something. Pinch is you doing the thing you want to do.
That's a good heuristic but it doesn't trump the fact that it is physically much more difficult than double-tap or tapping zoom in/out buttons when holding a device and controlling it with the same hand which is what you want 95% of the time. Pinch zoom is definitely less usable overall.
For example, when driving nails, in theory it would be great if you could just push them into the wood but in real life a hammer turns out to be handier.
BTW, not sure about ios but in android you can turn the +/- zoom buttons back on in labs.
For example, when driving nails, in theory it would be great if you could just push them into the wood but in real life a hammer turns out to be handier.
BTW, not sure about ios but in android you can turn the +/- zoom buttons back on in labs.