To each their own.

I genuinely find the data I track useful to reflect on what I spend my time on and whatnot, especially when I want to answer questions like: Did I get enough time off from work —and programming, in general— last quarter? Did I use the X program enough to justify a license renewal? How much time did I spend on meetings versus actual programming? Did I get enough sleep last week? Am I having lunch at regular times? How much time am I spending on professional growth? Etc.

And for the sake of clarification, I started tracking my own time long before I got my current job, so clearly, I do not do it specifically for my performance reviews. I simply happen to find the data analysis useful to support some things I say, and also, as some people say “the more data you have, the more accurate the prediction”.