Most Void Realm Illusion secret treasures of the tenth level were consigned for sale at places like the Fan Clan Shop and shops belonging to other top-tier powers.
Because if they were sold directly to a shop, the shop would force the purchase price down very low! To a powerful cultivator who needed one, a secret treasure was something they desperately craved. But to one who did not need it... it was truly useless! While some other cultivation paths were still quite common, the path of the Void Realm Illusion was relatively rare. Those who could reach the ninth level of the Chaos Realm without relying on external objects were rarer still!
'Buyers' were few and far between.
If a secret treasure was sold to a shop, the shop would naturally beat down the price.
Its owner was unwilling to suffer too great a loss, so...