DeBeers was essentially a cartel, serving in a role kind of like a central bank. They manipulated the supply to keep prices high and reasonably stable and also manufactured the demand out of thin air. Their power has waned some; diamonds aren't worth much second hand anymore, but they're still overpriced at retail and there's still the legacy of marriage conventions requiring a diamond, now with the additional caveat that it must be natural.
The idea of DeBeers is anathema to the ideals of crypto currency, even if the reality of it is far from perfect.
If millions find joy in having BTC in their digital wallet then I’d say there’s plenty of use for them.
The only reason diamond prices haven't cratered is because of a company propping them up.
The real reason diamonds haven't cratered is because they're a commodity that's always in demand - as long as people want to buy them they won't crater.