Well first off, just because a gun doesn't have perks doesn't make it useless by any means. I don't know about you but non of the perks in this game really stand out to me. If you're a pvp player and want to do the raid, I'm sure you've done enough pve to have at least a couple relevant pve weapons. Likewise if you're a pve player and want to do trials I'm sure you've played evough crucible to have a decent crucible weapon. Not to mention pvp players will always have an advantage over pve player in trials no matter what guns they have