I've read some interesting things about how when cats purr, the frequency emitted helps them to more quickly heal.
I'm not sure if humans can learn which frequencies to emit in order to heal specific maladies (would be something science would need to study). However, the fact that when you go to the doctor they never once ask you when the last time you did anything to lift your spirits was is very odd to me as a singer. Singing (and dancing, etc) lift up the spirits of us, and those around us, whether it be professionally, spiritually, or in solitude. Even "bad singers" can heal themselves from a bad mood to a good mood. You don't have to be good at something to enjoy the act, but I digress since that's not why most of us are here. Singing can help with chronic pain, according to this article: https://diymusician.cdbaby.com/musician-tips/the-healing-power-of-your-voice-7-reasons-why-everyone-should-sing/
and it's just good for us, like running or eating a salad or social time or drinking water. https://takelessons.com/live/singing/health-benefits-of-singing
The rhythm in music brings every single human together regardless of culture. We all understand that drum beat, as the sound of life. Music is such a vital part of being human that without we lose a bit of ourselves.
Why is singing important? Because it could heal us and others in many different ways, and it's simple, and free.