> You are grasping at unrelated analogies and contexts.

You're claiming that 8 character ids are inherently public. Why is the "publicness" of 7 numeral ids an unrelated analogy? After all, the universe of 7 numeral ids is significantly smaller than the set of 8 character ids, so if the former is private (by obscurity) then surely the latter is as well, absent some other factor.

So, what are some of these other factors?