Some people would like to keep on learning and they would like to do that by making sure that they will have more degrees. Some people would like to get an MA which means that they have a higher degree as compared to those who have graduated from college.
Those who would get the MSc usually need to get it so that they can be prepared to get their doctorate degree. This means that the MSc cannot be considered as a terminal degree.
When you say that it is a terminal degree, this means that this is something that a person can get that is considered to be the highest in a particular field.