The servers are already bogged down with people uploading thousands of fake coats of arms and photos that have absolutely nothing to do with the person they're attached to. How much slower will the site get if they add the ability to upload pre-recorded audio and video. We'll get people uploading some random song to everyone in their tree or a Gangham Style video to everyone in their direct line.
If you don't believe me just look at these examples:
http://buwt.blogspot.com/2013/01/model-of-idiocracy.html