Students frequently ask for an absence to be excused (for medical reasons, and so on). It seems that in Canvas, excusing an absence only means that a direct penalty won't be applied. I don't have "Grade Settings" set to deduct percentage points for absences, so excusing an absence has no effect on the student's grade at all. But the absence hasn't really been excused if the student's grade is the same as it would have been if it wasn't excused.

The point of excusing an absence is to not have that absence count against the student at all.

The only way I can see to actually excuse an absence is to mark the student "present," even though they weren't, which makes record keeping a farce.