[IlliOnato]

Sorry, by your logic an ISSN would be a good key for a database of scientific journals. It's exactly what ISSN is invented for! Right? Right?

Been there, done that. Journals that changed their names (and identities) but not ISSN. That changed the ISSN but not the name/identity. Journal mergers which instead of obtaining a new ISSN kept one of the old ones. "Predatory journals" that "borrow" an ISSN (you may not consider them real journals, but you've got to track them anyway, even if only to keep them from being added to the "main" database). The list may go on and on.

And don't even start me on using even more natural ID, the journal name, perhaps in combination with some other pieces of data, like year the publication started, country of origin, language, etc... Any scheme based on this will need to have caveats after caveats.

(A fun fact: there were journals that ceased publication but later on "returned from the dead". Such resurrected journals are supposed to be new journals and to get a new ISSN. Sometimes this rule is followed...)

At the end, a "meaningless number" you assign yourself is the only ID that reliably works (in combination with fields representing relationships between journals).

The problem with keys that "have meaning" is that they appear to carry information about your entity. And in vast majority of cases this is correct information! So it's almost impossible to resist "extracting" this information from a key without doing actual database lookup at least mentally, and often in your software too. Hidden assumptions like this lead to bugs that are really hard to eliminate. A meaningless number on the other hand does not tempt one :-)