Taking Charlotte as an example:
Charlotte is the world's most beautiful and desirable woman. She is supposed to be unobtainable. Seeing her fully naked now contradicts this.
She is not a young attention-seeker who posts naked pictures of herself on social media. She is a mature mother of two who is very protective of her image and cautious about who sees her body.
Charlotte is also the victim of various abuses, and her story revolves around learning to trust the MC, falling in love, and healing her trauma. When she finally undresses in front of the MC and allows him to make love to her, it will be a profoundly meaningful and deeply emotional event for her character. This moment would be less impactful if we have already seen her fully naked.
I understand people want to see her naked, we're supposed to want to see her naked, but the point is that you can't because she is currently out of reach. Charlotte will reveal herself when she is ready and when it is appropriate for her character, but that is still a long way off.