Agreed. Due to our size, we obviously have a significant system in place to track both the source and composition of the woods used in cabinet construction, in many cases this is not true and you get what you get (buyer beware). We use so much of these products that it's also in our interest to be sure that we are receiving what we are paying for.
CNC grade materials have different composition tolerances, the core plies are more uniform and the face plies have a guaranteed minimum thickness. The plies are usually thinner and there are more of them too, resulting in less warp and twist. For high volume precision production, this is critical because the reference for the cutter is off of the top surface of the material and if the thickness varies, this affects the depths of dados and rabbits, plus any other joints (like lock-miters) the cabinet may employ. The cabinet shop can go through more than a hundred (4' x 8' equiv.) sheets of plywood in a single day, it's not practical to struggle with pieces that don't quite fit together.
The advantage of CNC grades is uniformity (thickness, glue lines and lack of voids), the primary disadvantage is cost... but the end result is that it costs less to assemble and finish using CNC grade so in the end the cabinet is a much better product for not much more money.
The accuracy for CNC parts milled in production is typically between +/- 1/64" and +/- 1/32" resulting in cabinets that have tight, square joints. As you can guess, for the finger joints used in some of our natural finish guitar cabinets, this is essential or the parts simply won't go together.
Here's an video that shows cabinet production: