I am quite confident that a skilled musician with an iPad (or, even more obviously, an electric keyboard with a MIDI cable to the iPad) can create music that is indistinguishable from a human playing a piano. The synthesizer will be able to replicate the sound of the best concert grand in the best auditorium, direct to your studio headphones.
I'm also quite sure even unskilled musicians will prefer the feel of practicing and playing on a slightly out-of-tune old upright to a cheap electric synth-action keyboard or (ugh) a glass touchscreen.
I'm also quite sure even unskilled musicians will prefer the feel of practicing and playing on a slightly out-of-tune old upright to a cheap electric synth-action keyboard or (ugh) a glass touchscreen.
It's just a tool.