Have you ever even used a music app on an iPhone? They do not suffer from performance issues, even with several running at the same time. And Objective-C is not even garbage collected; it's reference counted, so I have no idea what point you're trying to make.
Having attended and played hundreds of rock shows throughout the world, I've seen many musicians use iPads as synthesizers, loopers, effects pedals, and DAW recording studios. I and all of my professional musician friends use it in performances for both audio and visuals. The audio latency and MIDI support of iOS is legendary among musicians, and is why they dominate the musical app market compared to Android with its unusable 20-300ms audio latency.
Having attended and played hundreds of rock shows throughout the world, I've seen many musicians use iPads as synthesizers, loopers, effects pedals, and DAW recording studios. I and all of my professional musician friends use it in performances for both audio and visuals. The audio latency and MIDI support of iOS is legendary among musicians, and is why they dominate the musical app market compared to Android with its unusable 20-300ms audio latency.