^^^ It's good that Sally occasionally doubles as a healer. She can keep Maple's already incredibly high stamina (VIT) from going down for a much longer time. Meaning more time to have fun together.
Also, the whole point of her going full defense is to not feel pain. If she was an M, she would not want to not feel pain.
There is a lot of MadoHomu on twitter if you look for it, just not a lot gets submited to Dynasty Reader.
The holy quintet in general has an absurd level of staying power, every single one of them seem to get new art on a daily basis, if anything it is a slow day when I don't come across one or two new Homu pics.