The situations vary, but there's normally more than one thing going on.
A product decision affects the market. The market affects the funding case. Funding affects what can be built. The route to market affects how the business needs to operate.
That's why I tend to be most useful when the answer doesn't sit neatly in one department.
You might already have good technical people, salespeople, marketers, finance people or specialist advisers.
My role is often to join the commercial thinking up, challenge it where necessary and help turn the decision into action.
Sometimes that means strategy.
Sometimes it means challenge.
Often it means getting involved and helping make things happen.