^^
Like I stated it is no coincidence that Natalia look-alike Barbara Palvin was cast and my guess is that Meisel probably shot the Natalia images as well. As far as the resemblance, again as I stated, flowy fabric, reclining position and a dreamy ambience is a fragrance ad staple, so it is not as if they duplicated a very unique concept, although I will concede that the ambience here was probably influenced be the ambience of previous Euphoria ads, which often happens if you stay in the same product family, The question I have is so what? Now if it was a crappy image, I'd be right there with you saying why the heck did they not use Natalia or use a model with a different look, but it's not, it's beautiful image, so I ain't got a problem with it.
P.S. I think you answered your own question with your comment that this product is probably targeted to a younger demographic, and while you are right that Natalia can probably pass for several years younger than she is, perhaps the fact that Barbara is a more down-to-earth version of the ethereal Natalia is the vibe that they are going for, and it is a more "on-trend" look.