Yes! We have 4 Rivers BBQ here in Atlanta, and this is exactly how they serve their food.
I've eaten out of these trays multiple times. They are washed between guests. It works fine for ribs and sandwiches and burgers and okra and green beans and fries. Not sure how well it works for saucier things.
About how this is more environmentally-friendly...
I suspect that the culprit is NOT the real ceramic plates, which we all know are environmentally-friendly, but the disposable dishes and even worse, the MELAMINE trays, which are really, really, really awful for the environment. Metal is recycled and re-used. Melamine, nope.
The problem with just going with a plate is that guests are going to ask for the trays. It would help over the paper plates, but then what about the trays?
From a cost perspective, there is less work in only having to wash a small tray, rather than a tray and plates. Plates break too and these metal trays are very sturdy. I suspect that Disney is looking at the bottom line and not just the environmentally-friendly aspect.
Of all the things Disney has done to piss me off as a consumer in the last few years (don't get me started), this one is not one of them.