User blog comment:B214/Volume 22 spoilers/@comment-95.90.227.198-20170201191840/@comment-30924344-20170203005126

@B214 Because her blessing doesn't infuse her powers into people, because otherwise what happened to Issei would have happened to Vali, Asia and Irina as well though much worse. The little power of Ophis Issei had inside him; he can handle it because he his flesh is made from Great Red's [it was reduced so he can handle it without injury]. Nobody else can handle just even a slight bit of her power, as proved by Issei who nearly died from it.