I think one key takeaway which isn't directly mentioned in the article is that UX designers, especially on custom-built business solutions like this one, tend to have a pretty rigid concept of the user flow. But the most useful and time-tested pieces of software tend to be the most flexible; the ones that empower users to do what they want, when they want, on-the-fly. That's what's so powerful about a whiteboard; not the fact that it isn't software. They're infinitely flexible and easy to manipulate.

Excel is an (eghem) excellent example of this concept in software, as pointed out by another commenter here. It doesn't presume a particular flow or even a particular set of user stories. It gives you the tools to record and manipulate large amounts of data, no matter what it is or what shape it's in, without writing code. That's a powerful concept and one that more designers should keep in mind.