Specially for urls this would be great. Currently if you need to link to multiple urls you have to create an url table and add multiple links from the current record to records in the url table. Besides, this won’t be well integrated (wiki style) in the record notes/description.
Trello mixes the concept of attachment and urls. Since Airtable already support a multiple attachment field, a generalization that sees urls as a kind of external attachment would also support the particular use case I described above.