I love the look of them, not pyjama-ry at all.
They’d look awful on me as I’m a short, slightly dumpy, 55 year old. But if you have the figure they look great.
I disagree with @Unshriven about needing to be young, I have some fabulous pieces that suit me (wrap around dress, wrap top, v neck t-shirts etc) from Fatface, it’s nice quality stuff too.
Definitely not pyjama-ish.