Not a counter-point, but: the other day I rebuilt my personal server, finishing by pointing the reserved IP at the new box. I then had a period of confusion because I was still seeing old content, because my browser (etc) was obviously querying the AAA record first, which I hadn't updated.
(a while ago I needed to contact support to get an IPv6 allocation at home, but that was a very quick interaction at the time)
About my only usage is to augment my isearch. I frequently use isearch to navigate to a place on screen, but sometimes there are so many matches it would take a lot of repeated "C-s" to get there. I have "C-'" bound to avy-isearch (from within isearch), which instantly turns that into one or two keystrokes to filter down.
(or I could pick up the mouse, I know, but that's not why we're here)