Enshittification is coming:
Beginning in the next month, when users click Bitly links or QR Codes, they may see a preview page prior to being directed to the destination URL. The page includes information about the link destination and may include advertising.
There are sometimes reason to use it. It’s shorter, so easier to remember. It’s also easier to send in text. I use a selfhosted shortener, so I can use these as dynamic links and can change the target if I need to while keeping the shortlink the same. But I agree that most don’t use it for respectable reasons.
It was useful way back but idr why? Like copying and pasting was always a thing, I think it was commonly used in yt videos with piracy links and they werent in the description.
It’s useful if you want someone to copy a URL from a physical medium, so they don’t have to copy a huge URL.
I remember seeing a zero width shortener, which uses invisible characters to encode your link.