When Peter Speake-Marin was touring his Thalassa with the SM2 movement last year he had one watch with AR coated sapphire and a second (which was finished at the last moment) without. It was very obvious to the naked eye (and the camera lens) how the movement and finishing just 'popped' and was much more impressive to view through the coated sapphire.
Remember also that the AR coating reduces, but does not eliminate, reflections. It absorbs most of the light spectrum but leaves the purple/blue reflections that are not as bright to our eyes - human eyes are less sensitive to blue colours. Note that there are some AR coatings that reflect green colours instead.
Andrew