Technically this is something you could already do, by setting a tag on a master keyframe and then going into an event sheet and setting up an on keyframe reached trigger you could then start playing an audio file in the corresponding action using the audio plugin.
The audio track just rolls all of that together and you can also see in the timeline bar the amount of time the audio will be playing in relation to everything else going on in the same timeline.
At least that is the main use case I was thinking about when I was implementing the feature.