Most teams have already been told to stop shipping outputs and start moving outcomes. Almost nobody is told what to do on the Monday morning after that instruction lands. You have a number to move and an open-ended, unstructured problem: which of the thousand things you could build actually moves it?
The Opportunity Solution Tree is the scaffolding for that gap. It is deliberately simple to draw and hard to do well, which is the usual signature of a real method rather than a diagram.
The hard layer is the second one. An opportunity is an unmet need, a pain point, or a desire that showed up in a customer's story. It is not a feature with the word "ability to" bolted on the front. Torres's own estimate is that the overwhelming majority of written opportunities are solutions in disguise, which is why the tree feels simple and then quietly collapses back into a roadmap.
Staying in the problem space is uncomfortable because it is the opposite of how most of us are wired. The tree's real job is to hold you there long enough to see more than one way out.