BuddyPress.org

What I posted was an example of adding a link to the adminbar, in this case, the Dashboard link for a Super Admin only, not for your specific scenario. Assuming you didn’t change the registration slug, it would be something like this

function register_link_adminbar() {
if (!is_user_logged_in()) {
echo '<li><a href="/register/">Use this link to register</a></li>';
}
}
add_action('bp_adminbar_menus', 'register_link_adminbar', 2);

Adjust as needed.