Having the rings to fill and maintaining my streak has been the thing that has motivated to get moving again. After many attempts to get more active so that I can be more healthy, nothing has kept me on it like this, and the responsibility of walking the dog twice a day that came home with us at Christmas.
Not having a good way to keep this data (and momentum!) while fixing a software issue I'm having with my phone is frustrating. I've lost 10 pounds through the month of January, met my move goal 65 days since getting my watch, filled all three rings for 40 days now, and I'm on a 30 day streak of hitting 10k+ daily steps. I currently weigh around 380, so these are all huge accomplishments.
In short, I strongly believe that recording (and keeping) the fitness data is very important.