I would imagine it is great for video evidence prior to officers with body-cameras arriving on scene. This footage may be useful in court. I could see utility in this for people calling 911 from under their bed or in a closet when there is an intruder in the house. It's probably also a good way to get a picture of an attacker that flees prior to officers arriving so they have an image rather than the RP's potentially sub-optimal description.

Small towns sometimes have law enforcement officers as dispatchers but I could see your point in big cities where dispatchers are less suited to see violence. On the other hand perhaps this may expedite a response when it's appropriate to do so. seeing it with their own eyes...

Volume up...no hiding. Volume down...no use.

I suspect people could avoid using speaker and/or the dispatcher can figure it out. They know how to handle intruder calls. Dispatch can mute as well.

There are likely many scenarios where the caller is not able to (accurately) describe the scene. The caller might be a child, scared & hiding, or injured.