Why is it useful? Web links at Jira are used to show all the links associated to an issue/record.
Who would benefits from it? Its easy for all users to view Aha! link at Jira epic or story rather than having it at a custom field.
How should it work? It should work similar like custom fields mapping, able to map jira's web link with Aha! URL at Aha-Jira integration.