My experience for UK and US (UK passport holder) - using Digital key works without human contact with hotel staff (unless there is a need for room reallocation after Digital checkin) however with a face to face checkin often requested to show a photo ID (either passport and driving licence).

Some continental European countries (plus Asian hotels) often don't activate a Digital key without showing some form of photo ID at reception which largely negates the benefit of using Digital key and bypassing the checkin line.