Ask HN: Venture Capital Method. Why? Why Not?

I've been looking at the theory of pre-revenue startup valuation and came across William Sahlman's widely adopted (I think I can say that) approach. This method is described mathematically in the spreadsheets found here [0].

I would like to ask the HN community for pro's, con's, objections and support for this method.

I realize this method starts with projections based on assumptions as to net profit at the exit point. Frankly, not sure how else one might legitimately --and fairly-- value a pre-revenue startup unless there's non-trivial IP or a prior round of investment.

If the startup is a slide deck and a working (hardware + software) prototype, it would seem that Sahlman's method is fair so long as the estimate of future net income is reasonable.

Anyhow, I'd appreciate reading opinion on this, particularly from those who have gone down this path. I have never raised capital and self-funded all of my prior startups. I am doing another startup and decided to consider going for external funding because it could help accelerate time to market and more. As I hinted above, this is a hardware + software startup with IP (provisional patents and trade secrets) and a nearly-ready-to-ship prototype that most customers would see as a finished product.

Thanks.

[0] https://www.vcmethod.com/