Without feed back, if there is some stiction during some part of the motion there is a real danger that the motor will stall and not move. The problem is then that the controller will assume that the motor has made target. Often what happens in this case is that the axis will dance in the same spot like an angry bee. When the controller moves the axis in the other direction is the positioning will be far advanced of the command position this may result in damage as the axis may hit the limits.