>The full URl to the original page.

I thought that was the standard in academia? I've had reviewers chastise me when I did not use wayback machine to archive a citation and link to that since listing a "date retrieved" doesn't do jack if there's no IA copy.

Short links were usually in addition to full URLS, and more in conference presentations than the papers themselves.

I think this is the only real answer. Shorteners might work for things like old Twitter where characters were a premium, but I would rather see the whole URL.

We’ve learned over the years that they can be unreliable, security risks, etc.

I just don’t see a major use-case for them anymore.