Simply put, before you can exchange for Rule Crystals, you first have to qualify for the exchange, which means you need to have spent contribution points up to a hundred. Only then will you have the right to exchange for Rule Crystals.
Each precious treasure within this bronze cauldron has a prerequisite condition; once you've met it, you can exchange at will.
This exchange rule, how should I put it, it encourages those in the Rule Integration Realm present to vigorously kill Black Demons in order to obtain the spirit materials they need.
But the presence of the bronze cauldron here, isn't it meant to enhance the strength of those in the Rule Integration Realm a bit?
Having such a threshold essentially makes the possibility to immediately enhance one's strength disappear.
The spirituality of this bronze cauldron always manifests very odd contrarian behaviors; it's unknown whether it's influenced by the Strange Heart Realm or manipulated by the Black Demons.