Black pearls have been removed from all seasonal reward branches since the end of fall season, and they currently only appear as epic or legendary drops during some events, in tiny quantities (100 and 225, respectively). Much like ice and fire shards, these seem to have been more plentiful in the past, and are very hard to come by now.
At this point, I’ve probably opened around 200 gold chests total. I’ve collected 3100 black pearls over the lifetime of this account, which means that if I used all of them, I could have a level 14 perch with an orange tier dragon on it. For comparison, I’m in gold tier; I’ve collected around 39k embers (13x), 22k fire shards (7x), and 19k ice shards (6x).
Perches generally don’t seem very valuable, but they can be a major source of points during feeding events, and it seems bad that a building type is effectively locked out for players who didn’t join before winter. I think it was good that pearls were removed from seasonal branches (because I don’t think perches are a top priority for anyone, and forcing players to pay sigils for them annoys them), but I cannot understand the logic behind setting gold chest pearl drops at 225 and 100, particularly now that they are the only source of pearls. They’re the least useful in-game currency and have the most tightly controlled supply.
I don’t think anyone wants the incidence of black pearl drops in chests to go up, but the quantity per drop should probably get a 5-10x multiplier.