Who it's for, and what it is worth to them

The commercial question is the same in every deal. What the answer is worth to you depends on what you intend to do with the company afterwards.

Independent sponsors and search funds

The problem: One deal, and you will be running it. The commercial case is not a workstream, it is the entire thesis, and you live inside the answer for the next five years. You are also raising against the deal rather than from a committed fund, so the diligence has to convince investors who were not in the room when you fell for the company.
What it is worth: A verdict your investors can act on, and a hundred day plan you can start the week you close. Whoever tested the commercial case is best placed to help you fix it, which means the diligence spend does double duty instead of being filed after signing.

The problem: The deal team is stretched across too many workstreams, the investment committee wants an independent read on a category it does not operate in, and the timeline does not move. The commercial workstream is the one most often covered by reading the management presentation more carefully than the last person did.
What it is worth: Documentation an investment committee can decide on: a one page verdict with explicit conditions, the price implications, and the evidence appendix behind both. Delivered inside the exclusivity window, on a fixed fee agreed before work starts.

The problem: You are taking a minority position, so you never get control and rarely get the access a buyout gets. The commercial case is a thesis about a company with a few million in recurring revenue, no analyst coverage, and a founder who is still the best salesperson in the building. You have days rather than weeks, the round closes with or without your conviction, and the question that decides the outcome, whether this motion survives being handed to a sales team, is the one a data room cannot answer.
What it is worth: A read on repeatability rather than on traction: which parts of the motion are the product, which are the founder, and what it actually costs to make the second one transferable. Delivered on a round timetable and written so it can go into an investment memo. After the round, the same work continues inside the company, because for a minority investor the commercial engine is usually the constraint on the next raise and the one thing a board seat alone cannot fix.

The problem: You hold for a decade, not for five years, so a commercial engine that runs out of road in year three is a worse outcome for you than for anyone else at the table. Software is also not the category you know best, and the usual checks that work on an industrial business do not exist here: no analyst covers a company this size, the competitive set is fuzzy, and market sizing is top-down and unfalsifiable.
What it is worth: A read on durability rather than on the exit: whether this keeps compounding without heroics, what the ceiling actually is, and which of the risks matter over ten years rather than over three. Then, if you want it, someone at board level who knows what was promised in diligence and can say whether it is happening.

The problem: You now own a commercial engine you inherited and did not build, much of which turns out to have been one person. The first hundred days set the trajectory and everything diligence identified expires quietly if nobody owns it. The board has financial and legal depth and nobody who has carried a commercial number in software.
What it is worth: An operating plan with owners and dates instead of a report, and someone in the room at board level who knows what was promised in diligence and can say whether it is happening. The commercial team you inherited gets assessed on what it can actually do, which is a question the org chart cannot answer.