Scam (mostly).

Hope, Hype or Shaky Science? Experts Fault $2.2 Million Veterans Study Involving Spinning Chair | NBC 5 Dallas-Fort Worth

The gyroscope does seem to help people with vestibular issues, though a study would be needed to see whether it is more or less effective then standard vestibular therapy. Apparently the study mentioned in the above article had no control group?!?!