If the kinked end had a point, I’d think it was a curtain-rod hook; the semi-circular curve goes over a curtain rod, and the point jabs into the curtain.
It’s just a generic hook. You can hook the small end over a something (like a wire shelf) and it won’t come off each time you use it like a regular S-Hook will.
ETA, scroll down to the pictures in the reviews to see them being used. This amazon page is the only place I could find them in use.
All the curtain hooks I’ve seen have looked like this. I’m not understading how it would work if one end was sticking out. It would poke through the fabric. Even if it’s not sharp, it would look all pointy from the front and probably still wear a hole through the curtain.