A few years ago I filed bug 148081, in which I asked for the build date to be added to the copyable version info, availale via Help > About. That bug was closed for a combination of two reasons:

1. The build with a certain (last) commit hash doesn't necessarily always get built on the same day, e.g. bibisect builds.
2. If the commit hash is linkified (e.g. on Bugzilla), one can follow the link and see when the commit is from.

That's nice and good. However, I've repeatedly been in situations where git.libreoffice.org was down, or otherwise refused my connections, meaning that following the link was not possible. Now, the first argument above would hold, except that I'm asking for the date of the _commit_, which unlike the build data, is a stable thing.

Adding the commit date will make it more convenient for users to realize what build they're running, even before following the link, or if they can't follow it.