The benefit would be if the downside of having one fewer person doing that work is less than the downside of multiple people hearing wrong advice from someone whose license implies they won't talk nonsense about healthcare.

I've no clue myself where the line should be drawn, but there's at least a debate to be had (by people who understand the scenarios a lot better than me). For example, would you say the same about a nurse who tells every patient they see that smoking cigarettes is the best way to prevent cancer, even if apart from constantly saying that they were doing a fine job in other areas?