In most ERC721
setApprovalForAll() implementations, to revoke approval, the mapping is set to 0, instead of deleting the entry. I wonder what happens if many users have many approvals revoked, wouldn't deleting save a lot of storage in the mapping?
To put it into code, it would look like I have a mapping:
mapping(address => mapping(address => bool)) private _operatorApprovals;
What is the difference between
delete _operatorApprovals[owner][operator]; and
_operatorApprovals[owner][operator] = 0;
Thank you in advance.