I am best known for my work with the Steadicam Zephyr (24lb payload). Below is some information and insight into the Steadicam's history, and how it is used.
At the 1978 Academy Awards, Garrett Brown, won the Academy Scientific and Technical Award (Award of Merit) for the invention of the Steadicam. Since it's first feature film production in 1976 (Rocky) to our present day, the Steadicam has become an industry standard in the film and broadcast industry.
The primary reason a Steadicam is used on location, is that it is uniquely designed to capture smooth moving organic shots that some camera gear cannot get without strenuous effort. Examples would be the one-take shot from Goodfellas, or the final training sequence from Rocky.