Yes. Often the need is best understood through iteration, but certainly having "eyes on" by the ultimate customer helps. Once I was told by marketing that security was not important. The customers got a prototype and screamed bloody murder. I think the moral of the story is to view the development of a product as a collaboration between all parties. All, including customers.

If there are silos of concerns then you can end up with a beer distribution game.

And this: "You measure progress mostly by how much you reduce uncertainty." is very succinct