What is the difference between the thesis/research paper streams and the internship stream?
The choice of streams is up to the individual student. In the past, it was generally believed that a thesis or major research paper was a necessary component of a Masters program for students planning to continue on and enroll in a Ph.D. program. Today, opinions are mixed on this. The major difference really comes down to the fact that the internship stream offers some (paid) practical experience that may give graduates an advantage in pursuing non-academic careers, while the research-oriented streams provide greater training in conducting academic research.