As for the scientific significance, the interesting thing is that it depends on who you ask. Many physicists would say that the important significance is that since this is the first direct image of a black hole, it’s proof that black hole actually exists. If you ask astronomers, since we were always confident that the black hole is there, we were more interested in what black holes do to their environment. Now that we have the image, we can see more clearly how black holes interact with their environment.