Thats an individual decision. I dont need both but by using both I achieve my best groups , especially when I'm using a loop. When I'm using a loop my release hand sits back too far to use as a consistant anchor point on my face so the kisser helps keep my anchor point consistant. When I'm shooting off the string I can ditch the kisser button and get a consistant anchor with my release hand on my jaw. Same with the peep. If you shoot better with it then keep it. If you shoot just as good without it then ditch it.