I was told by locals that it was explicitly to keep homeless people from dying. A few streets in the center were heated. Like, not warm in any way, but it was kinda weird to walk into the center and suddenly all the snow was gone. Just warm enough for it all to thaw.

Note, this was 20 years ago, maybe it all changed, either the system or the reasons. I can imagine that if you have a zero homeless strategy, it's weird to say that the street heating is for the homeless.