Sure, but we're talking Vim here. Is that more random than `"0p`? Or `ctl-o`? Or `ctl-6`? Mnemonics are important for operations we only perform a few times per day or every other day or less. But we're talking about a _built-in_ mapping for an operation that is performed probably as much as 1000 times per day, give or take. Convenience beats out mnemonics here because you don't need them (if you care to use it).
ZZ is just.. random?