Most ISPs who support IPv6 don't give you a single address, but a whole range (e.g. BT in the UK give you a /56). If you give your internal devices an address i

Most ISPs who support IPv6 don't give you a single address, but a whole range (e.g. BT in the UK give you a /56). If you give your internal devices an address in this range it means they are globally routable (obviously you will setup a firewall so the router doesn't allow arbitrary connections from the internet). If you have any devices you want to access externally, it means you can access them directly without worrying about NAT/port forwarding. Of course for most users it's going to make no difference at the moment, but for those who need it, it is useful.