in the old API, Kevingwang found out how to make a explosion sound play near a player. When MCPE gets note blocks, I hope there is a ability to play sounds near players with the new API. That way, a certain plugin can play music near certain players. For example, music will be played near certain players that chooses their music of choice. It could be a personal Radio!
It doesn't really need to be in the api, you could send a raw packet. I know pc has some sort of sound packet.
You still don't understand. The importance of API is not to make plugins easier to write, but to let them support different API versions and let different plugins work together.