As it currently stands the Sit Down emote is the most pointless stance in the game, even for RP as the player can just crouch and get all of the advantages of looking with the weapon and movement.

If you imagine sitting down with a one or two handed firearm, you should be able to turn your gun relatively quickly to acquire a target with ease, but with the current implementation of this emote, the player cannot move their gun to the left or right quickly and the restriction on how far the player can turn when in this emote is frankly too severe.

I am guessing this may be improved upon with the new Player Controller, but for now I will be unbinding this emote until it has been tweaked.