Good word ergonomics.
All the "but ipv6 is better because... xyz" just don't ring true to me, but I'm not a full time admin.
I still see "Quit remembering addresses - we have DNS!". My consumer equipment all have "192.168.0.1" and "192.168.2.1" type addresses. Relying on my browsers to be able to discover 'cable_modem.dyn' on a local network doesn't work - instructions will just say "go to 192.168.0.1" and put in a password. Good luck trying to get people to go to "[ff00]:0:0" or... whatever the heck you'd have to put in. Having foreign CSRs trying to explain what a square bracket is to people at home trying to set up a new cable modem... way too much headache.
And... there are millions of people that have to do this. There's perhaps tens of thousands of high-level network admins working to route everything through major global networks, but there's hundreds of millions of people that have to deal with and use all the stuff at the end points, and millions of us who serve as defacto "tech support" people for families/friends/neighbors.