You would still often need to parse them. Imagine that the url is the primary key of a table and the API changes url structure. Then you would get duplicate row

You would still often need to parse them. Imagine that the url is the primary key of a table and the API changes url structure. Then you would get duplicate rows and the only way to prevent that would be to validate the format of the urls, which is parsing. The index would also be bloated and slow.