Because many users are on tinder just for validation, and getting matches makes them feel good. They're willing to pay for it, so Match is willing to take their money at the cost of UX

Sometimes people want to match with someone in the town they're visiting (or moving to) soon.

Other times, people in poorer countries are trying to match with people in richer countries. Think of Tinder as acting as a broker in a situation that sometimes people call "mail order bride."

It kinda makes sense if you plan to be somewhere in a week or something and you want to try to link up with someone local.

More users.