Yeah, i don't expect it'll be implemented on BTC. Although articles you mentioned doesn't mention how it reduce size of transaction which already confirmed (inside a block), unless i missed something.
And technically, Bitcoin onchain transactions are not peer to peer. They propagate to the whole network. Lightning transactions, that's peer to peer.
So you don't consider a node as a peer in P2P/Bitcoin network? Why don't you re-read definition of P2P?