Thinking that providing additional context for commits is a waste of time is short-sighted. Yes, it requires more time and effort in the short-term (i.e. for creating the commit), but if it's a complex, long-lived project, then that extra effort will save a lot of time in the long run.

Sometimes the extra time and effort is already made up for in the review process, which without proper context could drag out and cause a lot of back and forth. Sometimes it might save somebody hours and days of investigation time. This is not to mention the benefits that both the author and the readers of the commit get by better understanding both the problem and the solution.