[AndrewThrowaway]

RTOS does not improve playback of music but is crucial if you e.g. want to produce music. Imagine a situation where you connect some MIDI keyboard and play some music - you want OS to produce the sound "real time" instead of "scheduling it".

[flyinghamster]

A good way to demonstrate the problem is by trying to use a music-making app through a Bluetooth headphone or speaker. That delay completely kills the ability to stay on the beat.