I use them primarily to lessen the perceived-burden on the user when I ask them to share something. For example, imagine you just checked-out on an eCommerce s

I use them primarily to lessen the perceived-burden on the user when I ask them to share something. For example, imagine you just checked-out on an eCommerce site, and a modal pops up: "Thanks for your purchase, share it with your friends: [SuperLongLinkThatWontActuallyTakeYouVeryLongToCopyAndPasteButForSomeReasonSeemsLikeAPainInTheAssToDealWith]" vs "Thanks for your purchase, share it with your friends! [short.url]" I'm actually asking them to do the same amount of work. But the first option seems like a bigger 'ask', so I default to the second one.