Formal business plans (at least for internet or saas companies) are wildly over-rated and increasingly unnecessary. They may provide more value in other indust

Formal business plans (at least for internet or saas companies) are wildly over-rated and increasingly unnecessary. They may provide more value in other industries (I have no/limited experience outside of internet/software). Prototyping is so easy, quick, and inexpensive. Why spend a week or two on a business plan when you can spend a week putting up a landing page, driving some ads at it, and then definitively get some data points on, "do people want what I'm about to do?"