Either go with a RD sight, or a laser module. Scope looks tacky as hell, and makes zero sense.
Don't care if it's a game set in the future. If you look at all of the human weapons Bungie put into the game, they all have elements on them that make sense; nothing out of place or wierd. As much as CMT strives to put their own twist on things, there are still boundaries between cool and dumb.