The point is, the field is not the appropriate place to be diagnosing and addressing mental health concerns. There are many reasons why this is a bad idea.
1. The subject, if in their home or "houseless location", has access to weapons and objects that can inflict injury on the social worker before any police can be called and respond.
2. The cause of the situation is likely to be still present, meaning no matter what is said, the person is still being influenced by that cause -- might be a person, an animal, ....
3. If the person has been drinking or taking drugs, no amount of expertise will let the social worker have a logical and long term conversation with the subject.
4. These situations often happen at night and in areas that aren't the safest. Even if the 911 reported situation is successfully resolved, the social worker is being placed in an environment in which they can face a number of unrelated risks just for being there at that time of night.
Mental health issues need to be confronted in an environment that can keep the worker safe from all potential dangers, with a subject that's not presently loaded or high, and where the location and time are less risky.
i foresee that rather than resolving the immediate problem, the social workers will more likely try to appease the subject and say whatever they think they want to hear. It might be the wrong thing to say if the objective is to solve the actual problem, but in order to avoid provoking or aggravating the person further, the worker will opt for short term peace over real and meaningful resolution.
Just my 2 cents.