This does not work if you want to use a hostname other than "localhost" (for running VirtualHost) pointing to your local machine.
You have 127.255.255.255 to play with!
Sometimes being understandable is more important than using the most precise and shortest notation.
CIDR is understandable for people who know basic networking. If someone doesn't understand what 127/8 means (which is totally OK if someone doesn't) I'd argue they shouldn't learn about the topic we discuss (valid HTTPS certs for localhost); they should learn something as basic as CIDR first. CIDR isn't difficult to understand. Basics first. You can't learn to speak English if you don't know how to open and close your mouth...