I would like to protect the MENU-Button in the toolbar with FaceID. When I hand my device to another person, the person should be able to use the browser but not to change settings. The other buttons should work as usual. I think it is enough to protect the (...)-Button.
Another feature I have not seen until now (but would be great) is that it is only possible to close the browser with FaceID. At the moment I have to use Guided Access as workaround.