Piped lets you view youtube videos without being tracked by google (and I guess without ads, though pretty sure uBlock Origin will do that anyway).
Peertube is like an alternative site to youtube. It's a different place to post your video (you can't use it to watch YouTube videos to my knowledge). The site is federated like Lemmy, and it uses bittorrent to download videos so people viewing the video at the same time will send part of the data to each other, reducing load on the server.
Peertube is like an alternative site to youtube. It’s a different place to post your video (you can’t use it to watch YouTube videos to my knowledge)
This is mostly right, I think I'd only clarify that it's not a singular site, much like Lemmy isn't, as instead it's more site software to spin up a YouTube-like video hosting site. Also you're right that you can't use it to watch videos as you might via Piped/Invidious, unless the creator has also posted their video to a PeerTube site/instance.
Last little point that's not super important to know for regular folks is that it's not using bittorrent for helping distribute video loads, it's WebRTC. Still peer to peer, just a different approach to it.