The purpose seems to be for when parsing a JSON document where large parts of it are irrelevant to your use case. It seems cursed, but it seems that using this

The purpose seems to be for when parsing a JSON document where large parts of it are irrelevant to your use case. It seems cursed, but it seems that using this method you can leave lee-way for unparsed parts and still validate what you are actually using, if the parser is robust enough.