(from Software Quality book)
One of the key elements of threat modeling is it's ability to highlight a variety of interesting issues and blind spots, in particular within the architecture of the threat model. One of my favorite moments occurs when the developers and the architects working on a threat model realize something that they hadn't noticed before.
In such cases, sometimes it is the developer who says, "Oh, I never realized that is how it worked!". Other times when the architect says, "Well, this is how app was designed", and the developer responds "Yeah, but that didn't work, so we did it like this."
What is actually happening when such exchanges take place is the mapping of reality, and the creation of a much better understanding of what that reality actually means within the company. Truth is being mapped, and the threat model becomes a single source of truth for the company.
It is very important not only to capture these success stories, but also to advertise and promote them. Promoting them allows you to explain one of the reasons why you want to work in threat modeling; because you want to understand what is going on, and you want to make sure that everybody working on a threat model is on the same page in terms of development, QA, testing, and so on.