User that are on shared hosters usually have no shell access. Since they have no means of runnung php extensions/RottenLinks/maintenance/updateExternalLinks.php manually they can't use this extension.
Is there any way, that extensions/RottenLinks/maintenance/updateExternalLinks.php can be triggered as part of running the webupdater (mw-config) so this extension can be used as well? The only workaround currently is to import a recent dump of the mediawiki DB into XAMPP und running extensions/RottenLinks/maintenance/updateExternalLinks.php in the shell from there and then looking up and changing each link manually on the live version.