NAT's only functions are:

- share a precious IP address at the NAT gateway border

- hide your internal LAN from external network mapper

Last point becomes moot when internal mapping software kicks in, legitimately or not, JavaScript or disingenuous application/daemon/app.

Welcome to Cybersecurity SecOP.

Now this is where Carrier-Grade NAT really shines: added functionality of handling mobile devices' changing IP addresses as it hops from one subnet to another (switching between G5/CSM/WiFi/personal-hotspot)