Why is collection approval required?

Collection approval is required to grant a permission for the smart contract access to specific types of ERC-721 or ERC-1155 tokens from your wallet. If you ‘list an NFT for sale’ or ‘accept offer on an NFT’, this approval process is required for the corresponding NFT collection. This process only takes place ONCE for each NFT collection, and a little amount of gas fees are associated with this request.

You may also be able to revoke this token approval if you don’t intend to use such a token again or in the near future. Please visit How can I revoke token approvals on Polygon? for further information.