Primarily it's a question of aesthetics. With movies/video clips there are generally two things to consider: picture and sound. The picture side of a movie is divided into scenes and very often the sound follows this rhythm, most notable in sitcom dialogs where one character usually gets to finish his line before the scene changes to another character saying her opinion followed by a cut to the first character - and so on. Subtitles not following this rhythm, overlapping scene changes, tend to be very disturbing to the viewer. So there's every reason to take this into consideration. The only problem is that with traditional subtitling equipment it's a rather time-consuming process.
With Sub Machine, however, we let the computer do the tedious part of the work. All you have to do is try to hit the scene changes when cueing. Even if you miss by as much as 10 frames, the computer will move the time code to fit the scene change. And even if you belong to that not-so-rare breed of subtitlers that prefer to place the cues manually instead of cueing on the fly, you can always fit your subtitles to scene changes later on using the fit cues to scene changes option. It will save you oceans of time and give your work a truly professional look.
