I love pajamas. I know, who doesn't. But I love all kinds of pajamas, I love warm flannel pajamas, I love diaphanous gauzy nightgowns, I love tight cotton T-shirts and boxer shorts, and I love satin men's pajamas. I don't remember if I was browing Macy's for Utena's manga pajamas in particular, or just for a satin set in general, but I do know that once I saw them, that would've been enough to convince me to buy them.
I can't imagine I'll ever wear these out, unless I'm ever at a con that's having a pajama photoshoot (I've heard those do happen), but I wear them often enough to bed!