The best and most applicable part of that article comes right at the end:
Mr. Reyes said that he and Mr. Agassi learned not to let the scale rule your life. “We had a little bit of a phrase,” he said. “The weight scale to most human beings can be like a Ouija board. It can start messing with your head.”
Honestly, I have to admit that I've been stepping on the scale recently, pretty much just because it's there. Of course, it didn't tell me anything I didn't know already. I'm about as fit as I have been in a few years and I want to make sure I don't lose (or gain) any more weight. I can tell with or without the scale that I'm on the edge – at that “ideal” level where losing more would hurt my running but also where gaining more would be adding unproductive weight I don't want to carry around. All the scale has done is confirm that.