IPv6 link-local addresses based on MAC address are neat, I use that in production.
We build a machine containing six cameras. All of them come with the same default IPv4 address, but the MAC address is based on the serial number, so the IPv6 address is, too. Employees enter the six serial numbers by scanning Datamatrix codes in order, and I can calculate the IPv6 addresses from that, connect and change their IPv4 addresses all in parallel.
Ten years ago I did the same thing on a different product with weird ARP shenanigans. The IPv6 approach is way faster and cooler.
We build a machine containing six cameras. All of them come with the same default IPv4 address, but the MAC address is based on the serial number, so the IPv6 address is, too. Employees enter the six serial numbers by scanning Datamatrix codes in order, and I can calculate the IPv6 addresses from that, connect and change their IPv4 addresses all in parallel.
Ten years ago I did the same thing on a different product with weird ARP shenanigans. The IPv6 approach is way faster and cooler.