It would be weird if this replaced the current display-less HomePod because people who put their HomePods in places that are not highly accessible would have a display that they can’t really use which is a waste, and people who pair their HomePods would have two identical displays near each other which is a waste, and people who use their HomePods as TV speakers will be forced to have speakers with out of place looking displays on them that will probably not be used because who wants to stand next to their TV to use a smaller screen? There are too many instances where you don't want your speaker and display in the same place.
And it would be weird if this replaced an ATV because why would anyone need a display on their ATV when it’s already hooked up to a giant display (their TV)? Plus if people already have better speakers then it would be wasting this device’s display AND speaker.
If this device is supposed to put FaceTime on your TV, then I presume you would get one of these and put it center with the TV? Again, it seems wasteful to have a speaker and display on it when you have your TV screen there and probably better stereo speakers. For those who do already have good speakers, a better product would simply be a small inconspicuous camera to attach to the top of your TV that connects (wirelessly or wired) to your ATV (probably cleanly hidden away in the TV stand).
It’s just weird to combine too many things into one device, unless it’s offered as an alternative only, not replacement.