So, if it was shot specifically for inclusion in a catalog, it would be okay, but since it wasn't, it's not okay.
If she wears it on the beach, it's okay. But if she wears it in a studio, it's not okay.
If thousands of people see her wearing it in person, it's okay. But if they see a photo of her wearing it, it's not okay.
If it has the potential to titillate a pedophile, it's not okay, but none of you are mounting a campaign against such images in catalogs, which certainly titillate a pedophile just as much.
No, I'm afraid it doesn't make any sense to me to have such double-standards, nor to bandy about what looks to me like made-up excuses and pseudo-justifications for holding to and making a stand for such double-standards.
And to revisit the "purpose"; What is the "purpose" of any art? What is the "purpose" of the statue of David or the works of Monet, Rembrandt, Picasso? What "utilitarian purpose" do they serve to justify their being made and displayed?