If you sign in, the site uses a session cookie so the account stays signed in. That cookie is not used to advertise to you.
The notice at the bottom of the page stores a single preference in this browser so it does not keep asking. That preference never leaves the device.
Pages you open may also be counted in the firm's own activity list when you send a form, request an appointment, or an administrator changes the site. That is an office log, not a third-party ad network.
You can sign out to end the session. If you arrived through a signed-in Grok session, sign-out may not apply, because that session is provided for you.