The key advantage to team supported divorce is that you get what you need from a professional whose experience and training enable him or her to provide you with the particular service that you require.
You may know a great plumber (electrician/framer/architect/engineer) who is potentially capable of building you an entire house, but you probably wouldn't ask him or her to do that. You'd hire a team, and each trade/profession would do the part they are most experienced with and trained to do.
The same is true with separation and divorce. For example, math is not the strong suit for most lawyers. If that was their interest, they'd be accountants or engineers. Similarly, while a lawyer may have very good listening skills and have great natural empathy, they don't have the training and experience to deal with an emotional breakdown as well as a mental health professional.
Another significant advantage of team supported divorce is that it costs less. This can't be definitively proven by a study, but some estimates are that team supported divorce can cost 50% less. The savings could conceivably be even more, resulting in some high conflict families saving tens of thousands of dollars.
In summary, you get better services for less money.