Best thing about Linux is the freedom it provides. You want a video editing tool, you just grab it from the repositories. Want an image editing app? You got it from the same place. Same for office suites. No need to go an purchase this and that piece of software. You can argue that the quality of the free software is not good enough. But that's quickly becoming more a myth than a reality. There are other reasons why professionals are using proprietary software. However, as I said, this is quickly changing.
Did you know that the visual effects in "The Man in the High Castle" series are entirely made with the (free software) Blender suite?