A few major reasons, one it's interesting to recreate environments and have something to listen to. Music has been and may continued to be use to invoke special emotions typical of a setting. I also like putting different notes together to simply experiment with what is possible.

On a more technical note, music is also heavily related to sinusoidal and frequency mathematics, so I am becoming more interested due to fourier series as an example. I may eventually branch out to become a larger musician as a hobbyist, not to be paid or own copyright. Most of the music I have listened to as of recent is an eclectic mixture of classical, orchestral, electronic, dance, edm, ambient, or sometimes jazz. Theater I rarely listen to.