In my experience, it’s a way of carry that may take a little getting used to, but I hardly even notice I’m wearing one anymore. It’s no more ‘jewelry’ than any other way of carrying, it’s just another option (and a less visible one). And no more hazardous than other ways of carrying, assuming you have the proper sheath/retention. I particularly like it when I want to carry a small fixed blade (which is most of the time), but don’t want to have a knife on my belt, for various reasons.
However, I only like small fixed blades this way – if it’s a full-sized knife, it either goes on my belt, in a pocket sheath in my coat, or in my pack.