I totally agree with your suggestion, and we (I am the author of this post) did spot-check the performance for a few common tasks first.

We ended up collecting all this data partly to compare machine-to-machine, but also because we want historical data on developer build times and a continual measure of how the builds are performing so we can catch regressions. We quite frequently tweak the architecture of our codebase to make builds more performant when we see the build times go up.

Glad you enjoyed the post, though!