I think there are two issues here in which eliding values from the middle of a string makes sense.

1. You want to refer to something in regular paragraph text, especially if you want to do it multiple times.  For example, here's a transaction: 4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b.  Satoshi made 4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b.  Actually, 4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b was the first transaction ever made, as 4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b was the coinbase transaction in the genesis block.

2. You want to avoid non-reading document interaction.  In this case, scrollbars make it possible to view long strings, but they aren't fun to use.  I'm always frustrated when I have to scroll back and forth in order to read everything.

    Worse, in fixed layouts (such as PDFs, ebooks, and hardcopy printouts), the text which runs off the side of the screen usually becomes completely invisible.  In print publishing, we usually try to keep max line length below about 40 em, although technical books do often use larger pages to allow a few more em.

I agree with your core point that we shouldn't elide anything essential; but I do think that we should try to format the document for the best reader experience.