I don't know if it counts as in practice, but I use the notation he chose not to parse quite a lot on internal networks..
ssh 10.0.0.123 is already a nice quick address to type out, but ssh 10.123 or ping 10.123 is even quicker.
Works in all kinds of random things. Web browsers of course, but games work just fine too usually, if they hand it off to the system to look up.
I write 127.1 all the time when I'm too lazy to type 127.0.0.1. Then I'm sad when it doesn't work because the nearest ip address parser wasn't written in the previous millennium.
Oh, yeah, and 1.1 is the only DNS server address I memorized.
I use mtr 1.1 all the time. (Like, literally all the time, I normally have it running in the background so I can see whether it’s my computer’s wi-fi adapter, the wi-fi router or the local ISP that’s playing up this time.)
I remember it was a few days after they came out with 1.1.1.1 and 1.0.0.1 that it dawned on my that I could drop the zeroes. I’d been wondering why they hadn’t chosen 1.2.3.4, but once I realised 1.0.0.1 was just 1.1, it became fairly obvious why they had chosen it.
(P.S. mtr’s stripchart with latency information is super great for this sort of thing; I have MTR_OPTIONS=--displaymode=2 set in my environment.)
I once used some of these weird notations to pack config data (mainly IP addresses) for remote installations into a product-key-like string that field techs could receive over the phone