For one, you explore and see a helluva lot more
I didn’t always used to run when I was on vacation or on a trip. I got into the habit of doing so a couple of years ago when I was in Surprise, Arizona (suitably). I was there to watch spring training games with a couple of friends, but I was also training for my first half-marathon. I had already made a lot of progress, and I knew a week of sleeping in, plus nachos and domestic drafts, would set me back. So every morning of my trip, I woke up an hour before my friends and set out on a run.
Since then, I’ve kept the habit, regardless of whether I’m actually training. I’ve run through the mountains in Salt Lake City, around all of Central Park, along Chicago’s Lakefront Trail, and down San Diego’s coastline. Aside from Central Park, these aren’t exactly bangin’ tourist hotspots. When you run through a city, you’re nimble enough to see a city the way locals do. And if that’s running the National Mall in Washington DC, well, you can soak up the tourist sites along the way, as well.