A lot of people have bike computers. I have one on my main commuter bike, but only because someone gave it to me. I use it mostly so I can see what time it is, and sometimes it's neat to see how fast I'm going. All those other things that people use bike computers for- miles ridden, cadence, average speed, heart rate- I don't need to know.
I don't worry about that stuff too much. The way I track things is how many days I commute. And even then, it's just a competition with myself. In February, the anniversary month of starting to ride to work, I had a good month in spite of the weather. I worked 19 days, cycling to work on 13 of them. March... not so much. I drove as often as I road (11 each).
Even though it's been stormy I can't complain so far this month- so far I've only driven to work 4 times and ridden 7.
I don't have the guts to sell my car and depend on my bike like some people do. I guess in that sense I'm a poseur. But I ride to work a lot more than anyone else I know.