Also ISBNs are really for retail ordering. Different sizes on paper have different ISBNs. An ebook need not have an ISBN. A revision (even if hard to see) will have a different ISBN for same paper size.
When we did a book library lending system each physical book got a unique barcode (different format to EAN/UPC/ISBN to avoid confusion). The ISBN wasn't used, except as extra book data.
The only value really of ISBN to a library system is adding fresh physical copies to the database as the ISBN can be looked up, ONCE.
Usually ebooks have the Author, Title and other metadata in the file. An ISBN is maybe only of value (limited) to find additional metadata or a cover, but the initial metadata is usually OK for this. So on Calibre I have no interest at all in ASIN or ISBN for ebooks. I might use ISBN just once on a paper book if I was adding it to a catalogue, library system or Calibre. I'm tempted to at least catalogue my approx 3000 paper books on Calibre, but the rest of the family doesn't use Calibre directly (it's single user anyway) and are happy to hunt the shelves for paper titles.
We duplicate any paper titles we like that come up cheap or appear as PD (I've actual paper editions to turn of 20th C and plenty of books by sufficiently dead people).
Mostly accurate
https://en.wikipedia.org/wiki/ISBN
I can't see why you'd sort by any kind of ID, either ISBN, ASIN or Calibre ID (any database will have a per record unique ID).
Edit:
The Country part might be where the publisher bought a block of ISBNs. It doesn't always mean the publishing country and certainly not the country of the author, which might be more important. I'd not even assume the language ID is correct. It might be the language selected at the time an ISBN block was bought. Technically it might just be an official language of the Registrant's Country. Thus a book with 1 (for English) could be in Irish, Manx, Cornish, Channel Is. Norman-French, Scot's Gaelic, Doric, Ulster-Scots etc. Maybe even in Maltese.