Hey, I can answer this. I’m from flat Southeast Michigan, I’ve been coming to Pittsburgh for vacation every year for the last decade. I'm not made of money, and I think Pittsburgh is the most accessible way to feel like I am a whole new world (geographically, culturally). Me and my partner can fit it in on a three day weekend.
It’s a great place to just walk and that’s the main reason I love it. All the neighborhoods are so unique. I usually do extreme 10mi+ day long walks… kind of an urban hiking deal. I’ve scoured most neighborhoods at this point and have a few neighborhoods on the bucket list still. Most of my favorites walks are on the hilliest parts (again, hills are great if you are from a flat area). Interesting history too, walking the slag in the 9 mile run and then going home and googling why there are slag mountains there. The parks and graveyards are great. I love finding a new set of stairs, climbing them, and entering a whole different area and a nice place to eat.
On a secondary note, I've found Pittsburgh also has accessible good food. Pusadee’s Garden is a good example of that. I am also Polish and love the range of polish offerings from Apteka to a random polish markets... I feel like I saw somewhere putting perogies on a pizza, lol. I have a large food bucket list at this point.
Other nearby cities like Chicago and Detroit are great but have nothing on Pittsburgh in my hill-walking-obessed eyes. Cinci is closer, but something is off about it (highways?). I dream to go to San Francisco someday and compare hilly cities.

Anyways, I'm here just to walk on your hills, not put my money in Station Square :)

We're miles away from becoming as tourist as New York or Bangkok. In the meantime a little extra business for the city helps make Pittsburgh more vibrant.