Video hosting is notoriously expensive. PeerTube circumvents this problem, because videos aren't stored on some single server, which would cause high bandwidth cost for the server operator, but largely by the users after they watched them, similar to BitTorrent. This way, the cost of video hosting is distributed among the clients, by using their internet connectivity for sharing.
I believe that PeerTube is an interesting project, and I'd ask you to check it out. It's cool.
Similar to Lemmy, it's not a single running server, but rather a software that can be used to set up a server. So there's many instances. I'm still exploring which instances are interesting. If you have any recommendations, I'd like to hear them.
With most videos on Peertube the server still has to do nearly all of the work. Optionally users can contribute bandwidth while they are watching but not after; how would that even work on a website that you close after watching?
Its a neat feature if a video goes viral or so, but Peertube still needs a lot of bandwidth regardless.
AFAIK, PeerTube still uses WebTorrent internally (could be wrong tho), and I wonder whether it could continue seeding back in the background after the tab has been closed, using some technology such as WebWorker or something.
I doubt many people would agree to that even on desktop PCs.
I think it would be better if there was a lightweight and easy to run headless relay that people could host themselves to help out struggling Peertube instances.
I could see them just having this as an option in a native client application. It could even let you pick and choose which instances, creators or videos you seed, perhaps even a "Seed This Video" button on the next video endscreen.
I think that less people would agree if it was a sort of "black box" of seeding, but I reckon a lot more people than you would think would go for it if they get to choose.
(Good) Pirates are already used to paying for their content with bandwidth and power usage ;)
Theres this old experimental tool called ZeroNet, and it had some really good ways of managing shared data. You could pin websites and files for other people to access, set limits, bandwidth, etc. It'd be nice to have something similar on peertube, like supporting certain creators by immediately hosting their videos for them. Maybe, for example, hosting their latest three videos.