The concept, popularized through Microsoft’s inclusive design framework, illustrates how accessibility features benefit a far wider group than people with permanent disabilities: captions help someone watching a video on mute in public exactly as much as they help a deaf viewer, and a large, well-spaced touch target helps someone typing one-handed on a moving train just as much as it helps someone with a tremor.
This framing is often used to make the business case for accessibility more concrete, since every sighted, hearing, non-disabled visitor will experience a situational limitation at some point in their session.