are you disagreeing with the statement that the more nodes there are (whatever you call them, wherever they are) the more transactions can be processed?
PoW protects from all nodes being in one location
Since "nodes"/checkpoints are based on transactions, that's kind of like saying, "are you disagreeing that more transactions means that more transactions can be processed?" Well no, I'm not disagreeing with that.
PoW only protects from all nodes being in one location (centralization) when it is simultaneously coupled with a limit to transactions per second, otherwise one physical location would out-compete others.