Occam's Razor argues that Sam simply wanted ScarJo's voice, but couldn't get it, so they came up with a legally probably technically OK but ethically murky clone.
You want Brad Pitt for your movie. He says no. You hire Benicio Del Toro because of the physical resemblence. Big deal.
Having seen "Her" and many other Scarlet Johansson movies, I didn't think for a second that GPT-4o sounded like her. On the contrary, I wondered why they had chosen the voice of a middle aged woman, and whether that was about being woke. It wasn't until social media went hysterical, I realized that the voices were sort of similar.
They're squarely in the zone with knockoff products deliberately aping the branding of the real thing.
"Dr Peppy isn't a trick to piggyback on Dr Pepper, it's a legally distinct brand!" might give you enough of a fig leaf in court with a good lawyer, but it's very obvious what kind of company you're running to anybody paying attention.