Using a media server is not similar to using a simple media reader, where you just copy/paste video or audio in it and read them later. Sharing contents implies that you can manage who will access them.
After submitting a video, it needs to be validated before it is made available online.
As such, consider these scenarios:
You just came back from holidays and want to show your photos and videos to friends on your TV set and also let them add comments. How about unrelated or inappropriate comments?
Your daughter would want to have her own space to publish her media and share it through Facebook from her laptop. Don't you think this should be supervised a bit?
Meanwhile, your kid wants the last Disney movie from the VOD provider on his tablet, right now! What about account credentials?