Using Grindr to find gym buddies?

Hey guys, I recently told a friend to be more careful with his phone (long story short: he had Grindr messages on his notification bar) and I ended up asking why he uses it. He said that he uses it to find gym buddies and that he's straight… do people do this? I thought that Grindr was solely hookup/dating app. (I've never actually used it at all so I have no idea haha)