Alright so I’m not an expert so I might not be explaining it correctly.
Federated Network: Multiple instances sharing content, such as Lemmy
Peer to Peer Network: There is no “instances”, just peers. Many peers sharing content. Every user is a peer. There is no server costs, because every device connected to the network is acting like a mini-server. It will cost your device some storage space and network bandwith depending on the how the software is designed.
Or do you think Centralized servers are still gonna dominate the future?
No, each user is a “peer”, in Lemmy they access content through the instances.
They are talking something more like IPFS.
I don’t really know much about IPFS, but I think a downside to peer to peer is the potential for content to disappear because someone turns off their computer or quits whatever application. I can’t be the only person to have a torrent stall at 80% because the rest isn’t available in the network.