It is challenging, and worthy to go there for the leadership modules, the power armors parts, and the loot/XP you get on the way. Many people did it during the first weeks of the server.
People do it less these days because :
- Many already have power armor/all leadership modules
- Many hate PVE, no matter the kind
- It is considered by some as "too safe".
- Currently, there is much less people than the early days of the server. Some don't want to abandon their pvp team and go to the dungeon, knowing that they will be missed on the battle. Some want to dungeon, but have troubles to gather three people that aren't doing PVP. Some other are too weak.