It's just a wig. It's a safe way to sport a new hairstylefor publicity, so if it doesn't work you can easily go back to the old style. I think Kubo Yurika and Nanjou Yoshino used wigs for certain shoots.
Right--but what's the thematic or narrative purpose of the whole makeover business? Liz is an entertainer (a musician, not primarily a model, or a voice actress playing different parts) whose public image was defined by her long dark hair. The whole shoot, in fact the whole idea of using Liz as a model for cosmetics, is Sumire's. The new look is "just as she imagined" (Chapter 11). (Incidentally, it also makes Liz look a lot like Maki.)
Even including a single panel of the ex pulling the wig off while they were making out would have clarified what the deal is here.
Sumire wants to change Liz's image to her liking, maybe even for business purposes as well. Hence the radical changeover.
Sigh. Of course that’s true—we know that because that’s what she does.
But neither of those answers can be the whole story.
If “for business purposes,” that makes no sense—if she needs a short-haired, light-haired model “for business purposes,” then why go out of her way to make over a girl with long, dark hair?
If she wants to remake Liz’s image to her own liking, then why have sex with her in her original hair?
You keep answering questions that haven’t been asked and ignoring the ones that have been.