tl;dnr: If you want people to adopt new tech that is WILDLY different from old tech, document the bajeebus out of it with lots of examples...
Do a page search for 'keyfile' on the RHEL 7 networking guide. You'll get one hit, and not a relevant one.
The guide only discusses ifcfg-rh which is a legacy transition tool at best - the official docs should do better than that.
The Fedora docs have a bit better coverage of keyfiles:
...but if you want to be real about it, even that documentation kind of sucks because it doesn't provide a solid practical example. Had to find one in the comments of a bugreport of all places (via google):
Just a complaint about the state of RHEL 7 docs in a couple places.