because we can pass packages in bulk between large distances… in routing, it’s always delivery boys: a single packet is a single packet: there’s no bulk delivery, except where you have eg a VPN packing multiple packets into a jumbo frame or something…

the comment you’re replying to is only providing an analogy: used to explain a single property by abstraction; not the entire thing

we can have staff specialise in internal delivery

but that’s not at all how NAT works: its not specialising in delivery to private hosts and making it more efficient… it’s a layer of bureaucracy (like TURN servers and paperwork - the lookup tables and mapping) that adds complexity, not because it’s ideally necessary but just because of limitations in the data format

routers still route pretty much exactly the same in IPv6 direct or NAT, but just at the NAT layer public IP and port is remapped to internal addresses and ports: the routing is still exactly the same, but now your router has to do extra paperwork that’s only necessary because of the scheme used to address