It’s weird, but it’s normal weird. It’s the kind of thing you see in design magazines and pinterest and the spruce. I don’t know if actual rich people do it but it’s definitely fairly normal middlebrow home decor.
(A lot of fireplaces in older US buildings are vestigial, often blocked up, and are inefficient at heating.)
The prose on that The Spruce link makes me hate the concepts of design, aesthetics, and houses.