A fair number of universities do this around the country.

It’s more efficient to have a steam plant than to have separate systems in each building. You get both heat and cooling with just a small steam plant on campus.

You save not just in energy, but also maintenance. If you have dozens of buildings each with several AC and furnaces, it’s a lot to keep running and replace every 20 years. Cranes needed for roof units etc. Steam systems are simple systems mechanically.

There’s likely other places where it’s economical to do this, but that’s the one that stands out in my mind.

If you went to a college with a large campus, there’s a decent chance they used steam.