Yaw/roll - affect on heading
If you keep the wings level, you will yaw and change heading, sideslipping by definition means you have a wing down...
The Brothers Wright inter alia used yaw for turning anyway. Roll control was just to stop the machine spiralling in. With increasing speed, and new thought, it was safer and more practical to alter heading with roll surfaces (ailerons, wing warping, spoilers, etc) than yaw surfaces (rudder) and the rudder became the stabilising device. It feels much nicer too to be in a careful coordinated balanced rolling turn.