but I fail to see how it would be as beneficial than the other, given that the bulk of the benefits falls on the user using the full node.
Pruned nodes are obviously not as beneficial as archival nodes but they are still beneficial to the network and contribute to decentralization of the network.
If the blockchain size grows even further, people that are hosting them on RPis and servers may not want to run it anymore.
In my opinion people running a full node on RPis aren't really helping anyone. They are more of a hobby thing to use rather than a serious full node set out to make a contribution to the backbone of bitcoin.