When sharing links with people in places where there’s a character limit or to avoid polluting visuals.

Also, when sharing like orally or showing it to someone else when you have no other way to communicate it: ex, the link of a shared cloud file

I think sometimes it gives people analytics on how many people click the link when the link is to something they themselves don't control. But I'm not entirely sure if that's a common service shorteners offer.

aesthetics

Easier to type when used on posters and other media where you can't simply copypaste

I find it handy for writing down a URL on paper

Easier to memorize/type, that's about it.
Replaced by (unsafer) QR codes as of late and can still hide analytics.