Worthless?- Maybe. Recognised?- Not by the ones that matter. I‘m sure your earned this milestone in martial arts using the best of your abilities in a thorough grading. The personal gains of achievements can be similar, however imagine this. A person opens a Martial Arts School in Taekwondo, then self promotes to an alleged Master grade, then teaches Taekwondo how they see fit without any formally recognised certification to prove he knows what he is teaching. Within a short period of time this man has taught 50+ people to Black Belt- for them to pass on. Within a 5 year period there are hundreds of people teaching what they don’t know to be true or the right way. Standards slip and Taekwondo as an Art suffers due to the pursuit of notoriety or money. I know this example seems a bit extreme, but Kukkiwon is there to ensure Taekwondo standards are monitored and maintained world wide. If you hold a Kukkiwon Dan/Poom grade you are internationally recognised for International and World Championships and such monumental events such as the Olympics.
See the previous Question above. If you intend to join a WTF style Taekwondo Club and instructors are claiming to be a certain grade, ask them to bring their Kukkiwon certification or Kukkiwon identification card (credit card size) into class. They will be the stated grade as shown on the card or certificate. If they only have certification for their grade from another organisation, do your homework and check if it is recognised Worldwide and especially by the World Taekwondo Federation (WTF)