Doesn't this go against the concept of flow http://en.wikipedia.org/wiki/Flow_(psychology) ?
The article is talking about on how to start tacking solving problems. People that are easily distracted seem to come up with more creative solutions. Which makes sense.
Also, the studies cited have a selection bias. They studied very smart college students (at Harvard), which means these kids, even though had attention problems, they were successful enough to get there, which means they are high functioning ADD/ADHD. (they manage to get some productivity out of them. And the extra creativity gives them an edge).
The article also mentions that they didn't measure all those kids with ADD/ADHD that were never able to finish high school, or get into college.
ADD/ADHD can be crippling, but for very smart people that manage it (or find way to become productive), it might be actually be beneficial to their creativity and give them and edge.
One comment that you hear from people that start taking Ritalin due to adult ADD, is that while they are a lot less distract-able and are able to perform and complete a lot more tasks, they feel less creative, and more a bit like robots.