This sounds like that if you don't trust a fortune teller, you can mitigate it by going to 4 different fortune tellers, and then somehow combining their predictions into your much more certain future.

Yes except in practice it's worked out more like this... Realistic is favored by tech teams. Optimistic is favored by salespeople and marketers. Pessimistic is favored by lawyers and compliance people. Equilibristic is favored by project managers and military.

Each stakeholder gets the kind of fortune they want. The important aspect (to me) is that the four viewpoints show all the stakeholders that their viewpoints are quite different.