Over 16 months, starting in July 2014, I lost about 60 lbs. A Fitbit was crucial to that process, since it showed me my calorie output. But, without monitoring calorie intake, the Fitbit would have been useless. Thankfully, there are good calorie-counting apps that sync with Fitbit (I used My Fitness Pal) and, in combination, they proved to be a powerful set of tools.

So there's nothing wrong, or counterproductive, about wearing a Fitbit. What is wrong or counterproductive is not understanding that calorie intake needs to be monitored as well; there's nothing magical about "10,000 steps" and it certainly won't much mitigate a crappy diet.