She is still fed Sakura's prana, just not to the same extent when Shinji has the Book of the False Attendant. Hence why she sucks ass even more than normal and Shinji has her eat people.
Again, it is not vital to her as a life-form. Also you're quoting the wiki again. Rider is not a "bloodsucker" even if she sucks blood because it is not vital to her as a lifeform.