Charlie59:
For PADI the masterdiver card is just for show. You don't do anything extra to get it except pay $35.
That is rather disingenuous.
Once the requirements have been met there is the need to pay to receive the card, sure. That's like saying that once you have finished college, you have to pay an application fee for graduation and a diploma (which you
do.)
The requirements are many, and adjustable to your interests. A
minimum of 50 dives along with
Five specialty certifications in addition to Rescue Diver certification (which, itself, requires that you have OW, AOW, CPR, and First Aid).
Those five specialties
each have (for the most part) multiple required dives, as well as books, classroom, and many have tests as well. No, there is not one
comprehensive written test, since that would require a
specific curriculum in those five specialty certs. Instead of
one final test, there are
up to five final tests.
The requirements can be heavy, even if a candidate were to try to pick the easiest (who said "fluff" before) specialties (Okay,
Boat Diver is not that tough...), there are not five fluff specialties generally available. And, that is beyond
Rescue Diver which is
not fluff.
So, once you fulfill all of the requirements, there is no
additional requirement save for applying for (and paying the application fee) for the certification. But, the same could be said for a neurosurgeon: Once he/she completes the requirements, there are no further requirements save for paying for the license and/or diploma.