Citadel is rubbish even if you want to do it for cosmetics - you can do your weekly run and get nothing (the loot there is piss poor so no point running it for gear). They should at least hotfix the thing so the weekly cache always drops 1 unowned cosmetic item/week (would still take a whole season to get all the cosmetics drops in there/they can add new stuff every 6 months or so).