Yes, although some colleagues prefer logging their time separately. The commit message allows only for specifying hours, the separate time-sheet entry also date and activity (i.e. designing, testing, documenting, and other non-strictly programming activities). It also allows to specify the same task several times, without having multiple commits :)

The concept of "activity" is interesting. I've created an issue to talk about it, thank you. https://gitlab.com/gitlab-org/gitlab-ee/issues/1304