Utillity skill choice
Some of those skills are just good all around for a game mode and some are good in synergy with another, which is why some posted builds have one slot empty for whatever but you’ll still see two together. There’s some trends depending on matchup also in WvW just as you’ll see less or more core thieves depending on matchup.
Some of those are junk but I think it mostly comes down to cooldown and how many traits you have to pack into one to make it useful. I’d change around a lot more if we had out of combat build loadouts.
Kash
NSP
NSP