Power
If you're a big shot in the industry, you'll have the power to hire a crew of musicians (and fire them too).
You'll also have some serious creative control over projects, as a musical score can make or break a film. A good score sets the tone, increases suspense, and manipulates the audience into feeling certain emotions at certain times.
Directors hand over their babies (films) to you, trusting you and your ability to improve the movie in ways that the filmmakers couldn't even imagine.
You have the power to move people with your mind, so to speak, by translating your thoughts into the music heard on screen. How cool is that?