Maybe 10 years ago or more it could have been considered fancy night gowns. But now, would you wear rhinestones, sequins, buttons, beads, and other fancy shiny stones to sleep in? I dont think so and if you did, that would be quite uncomfortable! What about the newest style-‘jumper robes’? which are sleeveless and you wear a shell underneath? Or the ‘wrap robes’? that have so much material one could have a very hard time sleeping in them? and of course, what about the price? who would sleep in a $200 (or more!) nightgown?!
I know nothing of this stuff, Boruch Hashem. If a Robe is really a Dress (by passing the “Dress duck test” then it is not a robe.