Lets say you want to be able to centrally manage call forwarding for all users. In freepbx 13 you could assign 1 user permissions for all. With freepbx 15’s dashboards you would have to create dashboards with hundreds of users on it to accomplish the same because you cant just toggle between users.
No way to manage this from admin either.
FOP2 will allow you to centrally manage them.
UCP 15 does look cleaner but UCP 13 had its advantages.