Arms on the cheek, in such a place, outdoors of a yogic posture, are culturally prevented, as a result of its a pose folks solely do when they’re mourning the lack of one thing/somebody. Therefore they apply a reverse logic in saying, utilizing it extra makes you duller and will increase the probability of mishaps and shit circumstances, which I assume you dont need in your life.
Meditation is usually completed in positions the place the backbone is relaxed but straight for energetic causes. Though the human backbone is supposed to be versatile, I dont assume its meant to be in such a place for prolonged intervals of time that are normally wanted in meditation.