Video safe areas

Action Safe and Title safe are only important if still delivering to NTSC or PAL/SECAM.  These formats are also referred to as standard definition full frame video.

ATSC may be simulcast to NTSC or PAL/SECAM, but how Action Safe and Title Safe are accounted for depends on the downconversion.  

DVD-Video menu design is another area where action safe and title safe need to be accounted for with variations depending on the title being Full Frame, Widescreen, Letterbox, or Pan and Scan.

Other types of safe areas may need to be accounted for.  Examples of this include in-show graphics that need to account for network safe areas (a style guide should be avaible from the network) and graphics created for vertical TikTok videos that need to account for the application overlays.

I've noticed that different TVs may display different amounts of the screen, so I've been using the action safe area as a title safe area.

It depends where the video is to be shown.

If it's for broadcast then they likely have tech requirements for safe and action. 
Otherwise, just good common sense about the audience.