The question I get most, usually from someone standing in front of a blank wall holding a tape measure, is whether metal decor reads cold. It doesn't, not once it's up. It catches light the way nothing flat on a wall does, and that warms a room more than people expect from something you can't put a blanket on.
In an ordinary room, metal pieces work best against softness, not against more hard surfaces. I've got a sun shaped piece hanging over a secondhand bouclé armchair and it softens the metal just by being near it, the same way a wool throw does on a leather couch. It also plays well with plants, oddly enough, the dark bronze or brushed finish sitting against green leaves like it was planned, even though mine absolutely was not. What I'd avoid is clustering it near a lot of glass or chrome, which just makes a corner feel like a showroom nobody lives in. Give it some linen, some wood grain, something with a bit of give, and it stops looking like it's on display and starts looking like it belongs there.
If you've got none of this yet, start small and start with one piece, not a set. A single wall hanging in a shape you actually like, not a trend you read about, is going to do more for a room than three matching pieces bought together, which can tip into looking like you ordered a bundle, because you did. I made that mistake with a set of metal stars that all went up at once and the wall looked like a motel. One good piece, hung at the right height, gives you something to build around later. Weight matters too, the cheap thin stamped stuff flexes if you tap it and sounds hollow, where a decent piece has a little heft and a dull, solid knock when you accidentally bump it moving furniture, which I do more than I'd like to admit. It also tends to hold its finish instead of going patchy after a humid summer, which matters if your apartment doesn't have great air flow.
It suits older homes with some texture already, exposed brick, worn floors, anywhere metal has somewhere to contrast. It also does something nice in a rental with plain white walls, filling space without needing paint or commitment. Good through every season, honestly, it doesn't fade or beg for rotation the way a lot of seasonal decor does.
Next time you're looking at one, check the back for how it's meant to hang and whether the finish feels sealed, not just painted, because that's what tells you it'll still look right in five years.