It’s still post processing to create a sound stage to a stereo signal. Nothing wrong with that, but for instance if I’m watching a movie on an iPhone or something, I’m assuming I can’t get the true audio experience of the film.
When it’s a movie I really am into, then I’m going to watch it in full surround, with discreet speakers. 7.1 to stereo headphones is always a compromise whether it’s Apple spatial audio, or Dolby Atmos for Headphones.
And absolutely I get your point, that it’s great for watching it at night. I’m just guessing their market for 4K Apple TV is more home theater people.
Usually when I’m watching at night with headphones I’ll be on the iPad.
Again it’s not that I don’t see the use case, I just wouldn’t call it “baffling” since the market is a little different.