Although Windows AD is always a default identity provider for AIM, in certain security plans it is desired for Windows credentials not to be used by any general PI users for authentication, but instead for credentials from a different preferred identity provider to be used. In such situations the wording "Windows integrated login" might be interpreted to mean that Windows Integrated Security (WIS) authentication can be opted for by using the button, when this is not true.
See What is the "Windows integrated login" button on the AVEVA Identity Manager (AIM) login page and how do I disable it? for full details on this button.