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?
Doable, not practical. Another major concern is the induced dizziness and general discomfort from such a small circumference. If you stand up straight, your head moves significantly slower than your feet. There are more effects that humans don’t do well with.
In addition keep in mind that this implies significant mechanical complexity the moment you don’t rotate the whole craft, but only a section or ring. If you do rotate all of it, simple tasks like taking a photo become… cumbersome.
Also like others have said, it’s not a permanent residence for anyone, and the main goal of the ISS is the study of low- or micro-gravity.