I'm of two minds. I can see all the points in the article for some plans. On the other hand, when I wanted to go on a 1,500 km bike ride, it was a plan before it's a reality because there's a path leading there. A fair bit of training was required as well as route planning, and finding lodging. At the same time I'd say we weren't terribly attached to the plan. There were days that we decided to ride less and stay somewhere else, and a massive re-routing part way though.
At work my plans tell me what I need to do and what my colleagues need to do to get the project done. I don't see success happening without them.
In both cases, though, I feel that it's not the plan that's the mistake but the attachment to it. If you've made a plan to go from Toronto to Montreal and are too attached to going by train, you'll be thrown off balance by a rail strike when a bus or plane might do. Or, for that matter, another city might also be just as good.