Based on the pictures I can’t imagine anyone legally living there.

I don’t know for sure, but I imagine usable windows are required for living spaces.

Every bedroom of a rental is required to have a window in New York.

But in this part of town, the advertising rights alone probably vastly exceed any possible revenue from renting the building for residential use. It’s kind of like the tiny building in Times Square that has the ball on top. I don’t think people even realize there’s a building behind all of the billboards, but it was original New York Times building.