We all know the pictures of the astronauts on the ISS floating around. We also suspect that a lack of gravity is bad for the body as the muscles go weak and such.
Why don't spaceships just rotate to cause the effect of artificial gravity through centrifugal forces?
That's the wonderful thing about a living language, if enough people start using a new word or a variation on the spelling of an existing one, it can simply become correct at a point.
The compound variant 'usecase' is often used in tech and refers to a very specific means in which a system is utilized.