A coupler with play in it is not overly bad, you should be ok to drive the car. The coupler is a composite plastic designed to take the harshness out of the equation with heavy rotors and the drive belt. It absorbs the energy.
Having replaced many couplers, a bad coupler is not typically visible. The holes in the coupler only need to be slightly enlarged to make noise.
The coupler'* only job is to couple the pulley/nose drive shaft to the front of a gear on one of the rotors. The rotors are timed together through the meshing of the gears. This meshing is not reliant on the coupler.
This picture is of the supercharger and it'* green coupler (replacement) on the 3 pins of the gear it drives.
This picture is the nosedrive/shaft side. The three pins slide into the three remaining holes on the coupler pictured above.
The most mileage I have seen on a coupler is around 140K, at that mileage I could not visiibily see the elongated holes. After a coupler change there was no slop when rotating the pulley back and forth.