Collectors are the end buyers, who ultimately create the value; but the existence of collectors as a predictable sink, permits the trading of the thing they collect as a medium of exchange and (short-term) store of value.

Similar to fine art. For every purchase of a painting by a collector who's actually going to display it, there are 10-100 being purchased by people who're going to keep them in freeport awaiting resale.

Basically like commodities futures. You don't buy onion futures because you have anything you would personally do with multiple tonnes of onions.