The second 64 bits are reserved for future innovation. Ethernet nodes happen to populate it with tedious junk, but that forces ISPs to allocate a /64 per user

The second 64 bits are reserved for future innovation. Ethernet nodes happen to populate it with tedious junk, but that forces ISPs to allocate a /64 per user as a bare minimum. Over the coming years and decades, people will repurpose those bits to do interesting stuff at the network edge, without forklifting the entire Internet again.