I TA'd in the attendance office at my high school back in the day.
The city's tracking of student attendance only lasted a portion of the year or a portion of each quarter.
During those times, much more effort went into calling the homes of missing students and finding out why they were not showing up to class.
I remember asking about why all the calls were happening or not happening and it was sort of quietly explained by the staffer: measurement of attendance affected how the school was being evaluated by the district. Presumably, budget was hooked to it in some way.
I didn't make any waves about it because "working" in this office was super powerful and the staffer always brought in cookies for us. Amazing gig.