The Coanda effect is used very effectively on McDonnell Douglas's Helicopter models, and specifically the ones without a tailrotor. On these models the cylindrical boom has a lengthwise slit on one side through which air from an internal fan is blown out, downwards past the boom surface. This, coupled with the downwash from the rotor sets up a sidewards force created by the fact that the airflow past the boom on the side with the slit is higher, and therefore the pressure is lower (a bit like the interaction between the top and bottom wing surfaces).
What's good about this you might ask? Well, as the intensity of this force is controlled by the amount of downwash from the rotor, an increase in rotor speed will increase the side force and presto: there is no need for a rudder input as this automatically stabilizes the helicopter directionally! Of course there is still a need for rudder control and therefore there is a movable tailcone at the end which can direct a blast of air from the same internal fan to the right or left.
The Coanda effect, used here for getting the downwash to follow the tailboom contour, is therefore not totally useless in aviation!
As for how this applies to a wing: as a wing is not a cylindrical shape, the Coanda effect is not applicable here. So rest assured, your basic PPL aerodynamics are not affected by this in my view!