My 3rd grade daughter was unlucky with various illnesses and missed about 12 days this year (so far). I got a letter from her principal attempting to guilt trip me for her "Chronic absence".
I wrote an angry response (in retrospect it was too angry since he had no choice about the letter) where I asked if he would prefer my sending sick children to school.
Her grades (for whatever value grades have in 3rd grade) are fine. I'll take the chance on her reading her "Diary of a wimpy kid" book when sick, or when a sane system would have given a snow day.