The "turning" can trick you into feeling motion. The same principle is at play with numerous roller coaster rides in various parks (i.e. star tours, back to the future, etcs...) and you are right that it won't accurately represent "Gs" the way the real thing should, but it will give you a feeling of movement and motion going up, down, pitching, sliding, etc.
It's definitely not for mainstream use, though. It would be cool to play with a couple of times.