Ready-to-go supplies and classwork presents a polished, professional image for guest teachers and immediately signals to students that this is not a "free day."
Happier office as staff can focus on THEIR responsibilities rather than last minute preparations and emergencies when teachers are out
Ample supplies and classwork to keep students engaged and reduce empty class time (where most problems occur)
Issues related to substitute teacher are reduced or eliminated which allows for admins to spend time on larger tasks