From the point of view of an open-source intelligence (OSINT) researcher or hacker conducting recon, dating websites are a unique collection of searchable databases. Researching a target via dating websites can reveal a few kinds of information that are useful for a hacker.
If you know where a person hangs out, you can locate their Tinder profile using the Chrome browser with a GPS-spoofing extension enabled on Windows or macOS.
People often use the same screen names, and you can often track a person across the internet just from finding a frequently used alias. Since many users also link their Instagram profile, intercepting a screen name can be the key to someone's entire online existence, if they tend to reuse the same one.