If you're only interested in translation jobs, there is no need to upload a video.
But the majority of our efforts focus on generating interpretation jobs. We generally do not extend invites to users who have not uploaded a video. We've consistently received customer feedback that these videos are crucial for customers' decision process.
Hence, the videos are not required to be registered on the platform, but they significantly improve your likelihood of receiving invites.
And the videos are private and cannot be indexed by Google or seen by other users. The only way a client sees a video is if the interpreter authorizes it.
Please also see this article on who can see your video self-introduction.
Here's an example of a great self-introduction video: