Well crap. I was used to going to 1.1.1.1 on my cellphone when on wireless APs that tried to redirect you an agreement page. Now there is a valid cert/website at that address.
Don't some VoIP devices use 1.1.1.1 too to check connection type or something?
There was a paper from a couple years ago when 1.1.1/24 (or bigger, don't remember) was still unassigned; at some AS they logged what kind of traffic was targeted at that subnet, by IP, port and protocol and 1.1.1.1 stood out. Can't find that paper just now unfortunately. :-(
Never had any issue and there's an extremely low, almost infinitely zero, chance of the domain dropping and being taken over by squatters (re: neverssl)
Guess I'll have to pick a new one.