Exposed drivers distract me from the sound and the illusion. With those grilles in place,

That is the first time I’ve ever seen a reviewer express the same sentiment I share regarding speaker drivers and grills!

When the drivers are exposed – and quite a few speakers feature particularly gauche-looking arrays of drivers! – the visual cue always makes me conscious of the fact of where the sound is actually coming from. A drum cymbal shimmer will “come from the tweeter” – hey isn’t that a great tweeter!?? Etc.

With a good set of grills on, for me the speakers better remove themselves as obvious transducers of the sound. They become more like pieces of furniture around which the music just appears.

This is why for me it’s optimal for a speaker I’m looking at to be designed sonically to work best with grills on, as well as aesthetically. One problem is that so many speaker manufacturers seem to expect audiophiles to listen with drivers exposed that the grills are offered more as an after-thought. And they look that way: sticking out in an ungainly way just plastered to the speaker.
Where some manufacturers do a better aesthetic job of integrating the grills in to the design. (My current Thiel 2.7 speakers are to me a perfect example. Sound great with the grills on, and look extremely elegant and coherent with the grills on).