how come no one ever uses befallen?

Necromancers.

Befallen is another great zone to get XP and some decent items in. I leveled up a few of my characters in there! Dying deep down inside sucks but it's often easy to get someone to head in from East Commons to help with a CR. I often pop in to buff up players in Befallen.

Najena is another fun zone to get some XP and items in! Both places are a bring your own group place but I often see people forming up groups for Befallen.