If without dives, then it is a "recognition" card and if it is with dives, then it is a "certification" card. NAUI doesn't issue "certification" cards to divers/students if no diving was involved per standards. I don't know why would anyone want a "diving" "certification card" without doing dives. I require dives for the Nitrox certification where the students need to demonstrate proper and independent dive planning and gas management using various mixes of nitrox (tables, MOD/EAD/Best Mix calculations, gas supply, dive computers use). The first dive is a general review dive for all skills including very basic skills and buoyancy control in addition to the nitrox specific knowledge.
In my view, I don't understand the people who are advocating the watering down of the training and knowledge for Nitrox use for divers when many of them complain about the low level of diver general training and competency out there. It is true that one can argue that for the recreational use of nitrox, one doesn't need to know much more than "breath in, breath out and don't go deeper than your MOD" but this is just like saying "one doesn't need to know much more than "breath normally, don't hold your breath and don't exceed your NDL's" when they want to learn how to scuba dive in general. Just total BS!
I am not a "c-card" reseller, I am an "educator" and I take every opportunity and responsibility to train and educate my students in all of the courses I teach and the consequential certification cards offered and given to my students. The theoretical knowledge of nitrox use maybe "simple" if one wants to teach to the absolute lowest common denominator and just get it over with and issue the card in the shortest time possible, but they are missing a great deal of usable practical knowledge and skills in their training programs their students should receive and master. I see that the greater majority of divers out there lack in proper dive planning knowledge and skills without nitrox and if they don't learn how to plan and conduct their dives properly and then add the nitrox to the mix, it makes it even worse. Students deserve and need to practice the planning and conduct of the dive under the guidance of a professional instructor in a nitrox course.