That's nice in theory. In practise though im doubtful. Churn is going to be much higher on something like peer tube than something like traditional bit torrent. Access patterns might also potentially be distributed badly for some videos.
Not to mention the long tail of less popular vidros.
If the issues you are worried about aren't present yet, then logically right now it would be a comparable to and a competitor with YouTube. People in the main don't avoid web services because of hypothetical technical problems that might exist in the future but that the design seems superficially resistant to.
PeerTube actually does have technical issues in there here and now, but the number one problem is just that YouTube is an excellent service preferred by both users and advertisers and PeerTube doesn't seem able to outdo it in any meaningful way.
But did you watch it from a site operating at scale? Its easy to be youtube at low scale.