In my opinion the traffic estimator is very inaccurate in predicting how much traffic you will get from adwords. But on the other hand it is a good "indicator" to show you how hot a niche is doing comparing to the other niches. How would you use the results from traffic estimator and how would you interpret the results?
For entertainment pursposes only. In all seriousness...the only thing I use estimates from the tool for is to decide if traffic potential is "high" or "low". Trying to get any more refined than that is a waste of time.
The traffic estimator is intended to give one a ball park estimate with which to start. Then, let the campaign run for a time, monitor what happens in the real world as the competitive landscape changes, and adjust your budget and Max CPC settings from there. I'd also suggest starting out with a daily budget and Max CPC that you are comfortable with, but no higher.