The punchcard might conceivably be useful for attempting to coordinate with the developers at the time when they're most active. Other than that, it does sort of feel like they just had a bunch of data lying around that they felt really needed to be shoved into a graph.

It's interesting to look at major projects that have many commits to see when their active hours are. For instance, this is Linux's punch card: https://github.com/torvalds/linux/graphs/punch-card

Of course, interesting != useful

Wonder if that's adjusted for timezones. Would be nice to have a checkbox to either align by UTC or the commit's timezone (if that's even available).

It actually plots the local time, i.e. a commit at 3am PDT and another at 3am EST would contribute to the same circle on the plot. (I did a clone of the old GitHub graphs a while back.) So it isn't really useful for knowing when to contact faraway developers. On the other hand, it is fun to see how many committers are regular night owls.

I don't know--looking at the punch card gives me a good idea of when contributors to a project are active. This could be useful if I want to contact them about something over IRC, for example.

Also, it's just amusing to see people I know regularly comitting at 3am.

I totally agree with you. The traffic chart is also very exciting.