The title of this should really be "why you shouldn't use 3rd party link shorteners". There are lots of good reasons to use internal shorteners (and this article even ends by telling their own users to use their internal gov.uk link shortener).

At reddit we had a link shortener (redd.it) that was automatic for every post, which was useful for posting on social media, especially twitter, when the limit was 140 charters. There are lots of other uses for internal link shorteners too, like just having nicer URLs for publishing or saying out loud.

But yes, the article is totally right about 3rd party link shorteners.