When I ran this experiment it was pretty exhilarating for a while. Eventually it turned into QA testing the work of a bad engineer and became exhausting. Since I had sunken so much time into it I felt pretty bad afterwards that not only did the thing it made not end up being shippable, but I hadn't benefitted as a human being while working on it. I had no new skills to show. It was just a big waste of time.
So I think the "second way" is good for demos now. It's good for getting an idea of what something can look like. However, in the future I'll be extremely careful about not letting that go on for more than a day or two.