I’m here to vote for this feature! I am working on projects that require the site to be “live” for not just webhooks but e.g. for WooCommerce payments that requires JetPack. When I override siteurl and home using e.g:
define( 'WP_HOME', "https://username:password@incandescent-grain.localsite.io" );
define( 'WP_SITEURL', "https://username:password@incandescent-grain.localsite.io" );
(Note, I’ve even tried setting siteurl and home directly in the DB too)
…you can see that having to include the username:password bit causes issues with CORS.