One of the major advantages of streaming technology is to be able to play a movie directly from a website without having to download the whole file. The movie starts playing after a very short buffering time. Rewinding or forwarding through a movie in real-time is also possible without having to download the entire movie.
Additionally, a streaming server is able to automatically reduce the quality of the transmitted content depending on your connection speed or push it back up to the maximum available resolution and frame rate on a fast internet connection, without stopping the transmission.
Another benefit is that streaming a movie provides a simple way of copy protecting your content, as the user will not be prompted to download or save your file.