The practice is old; I remember it being used by the petroleum companies and other corporations in the 1950s.
International companies used it in management and technical training to give varied experience to valued employees. A Colombian or Indonesian, e. g., would be transferred for work periods to jobs in company locations around the world, including the U. S. and Canada. Specialists also were put where they were needed.
A company operating globally with thousands of employees must make the best use of them, and keep their expertise at a high level by training and varied experience.

The medical and health care fields are always short of staff. Here in Canada, doctors and specialists in radiology, etc., move to private practice, higher end jobs or clinic ownership after they gain experience and financial credit. There are too few young graduates in these fields, and the result is that workers are brought in from overseas. Rural locations are not favored by ambitious workers or those who want the advantages of a city, and workers must be recruited from overseas.

The system does not screw workers in the medical fields; the truth is that there always is a shortage of workers and governments and medical facility managers don't have the cash to pay the same wages to all workers or pay extra allowances to those working in rural or other 'undesirable' locations.