In the competitive framework, medals are the coinage of the realm--with a hierarchy of local, regional, national, and international circuits that serve as the proving grounds. In this ecosystem, it's clear as day that not all practitioners and competitors are created equally. The same can be said both at a time between competitors and across times. So, for instance, being a multi-time world champion as an adult in jiu jitsu is more impressive and significant than being a master or senior world champion merely once (as impressive as that might be when viewed from yet another scale of analysis). While both are impressive accomplishments--that often go together as today's world champions are commonly tomorrow's master and senior world champions--no one should pretend that the former and latter are somehow equivalent in their magnitude and significance. All other things being equal, the winner of ADCC is a better grappler than the winner of a regional NAGA--even though both may hold the same belt.
This kind of hierarchical competitive framework is something one is well aware of growing up in other grapplings arts. For instance, being a state champion from Iowa or Pennsylvania has always meant more than being a state champion from Florida or Georgia (which is where I grew up) just as being a national champion is less impressive than being a world champion or Olympian, and so on. So, one's skills and accomplishments must always be relativized to the appropriate scale or competitive niche in order to serve as a useful tool of comparison.
It is partly for this reason that belts and belt progression are helpful. They relativize individuals both to lineages and affiliations across times and during times. If you tell me that someone is a multi-time world champion at white, blue, purple, brown, and black belt who trains under the Alliance banner, I know what that means--namely, they will easily submit me as well as most of the people I have ever or will ever train with. In short, once properly relativized, our respective places in the overall and ever-expanding evolutionary ecosystems is well-established. As someone who grew up wrestling and competing successfully in the south and someone who competed both as an adult and as a senior in jiu jitsu (at the regional, national, and international level), I know my place. I have earned gold and silver at local tournaments and lost embarrassingly during the the first round at the Pans.
But once we leave the competitive realm, where it is easier to know one's place in the respective hierarchies--belts replace medals as the local coinage and things become inevitably murkier. To the untrained masses who serve as possible consumers, customers, training partners, and fellow students, belts and lineages serve as surrogates and social signifiers for legitimacy and success. At this scale of analysis, black belts trump brown belts and so on, down the line. So, a gym with a black belt (or multiple black belts) will tend to garner more interest than a gym with only a purple belt (although, this, too, used to be different when there were not many black belts outside of Brazil). But even here the belts are still scale-variant. For some black belts are hobbyists who have never competed, some are former or active competitors, and the competitors can be further broken down based on the strength of their accomplishments etc. Moreover, this scale-variance is further complicated by the unique goals, needs and interests of the practitioners themselves--e.g., I am less interested in whether someone is a world beater and more interested in whether they are a good instructor.
Yet further compounding matters is the fact that competitive success is no guarantee of pedagogical success. After all, lots of great champions make for horrible teachers and vice versa--a number of great teachers were never great competitors themselves. So, while competitive success and medals serve as proxies much as belts (or lineages) serve as proxies at other levels, there are never any guarantees. So, the respective tokens of success in jiu jitsu--medals, on the one hand, and belts, on the other hand--can and should be both scale-variant and relativized to one's own uniques interests and preferences. As a practitioner, competitor, student, or coach, one will always do well to keep this fact in mind--which will help instill a sense of humility when it comes to one's place (or lack thereof) among the pantheon of jiu jitsu greats to one's place on the regional competitive circuit or even one's place within one's gym or affiliation.
It is this perceptive that will ultimately help one make progress. For my part, I am a busted up but grizzled purple belt with more teaching experience than is common for someone at my belt level. I am also someone who has spent enough time on the mats to know my strengths, weaknesses, and limitations. But for all that, I am no world beater--and neither are my training partners. But I am comfortable in my own skin just as I am comfortable with the scale-variant nature of my successes and failures--both locally and more broadly. I would like to think this makes me a better training partner, student, and instructor. If not, perhaps more deep thinking about medals, belts, promotions, and scale variation might do me some good. I could also just go to open mats and try to enjoy some flow rolls--which is all I really have left these days anyway (other than early morning missives here at The Grumpy Grappler, of course).