Nardah is used by people who do pyramid plunder but didn't get a sceptre yet. I never thought I'd say this, but with pyramid plunder thieving is a fun skill to level AND the xp in there is crazy. Also the shop there has a lot of chocolate in stock to help with herblore or making cakes :P As far as useless features go, think making fishbowls with pet fish, getting a pet rock, mudskipper hats, crocodiles, and the list goes on...