The issue which precludes granting supressredirect to autoconfirmed users is that old pages may have links that would get broken. On the other hand, the main use case for moving without a redirect is when a user creates a page with the wrong title and has to move it, which then requires them to ask an admin to delete the useless redirect. So it makes sense to allow the creator of the page to move it without leaving a redirect when it has been recently created (say, 24 hours). (It would also make sense to allow it for old pages in their userspace (e.g. draft articles) but that's a special case of T71162.)