There has been so much confusion around this product that I think the actual explanation is going to end up being so simple.
Mark Gurman has said the smart home display will have a rechargeable battery, and several different mounts and stands you can connect it to,including one with additional speakers.
That will be the new HomePod. It will just be a base for this new screen to be attached to, probably magnetically.
Other accessories that have been mentioned that will also probably work magnetically are wall mounts and desk stands.
It’ll be just like the pixel tablet and it’s speaker docking station.
What it certainly won’t be is the HomePod as it looks now, just with a 7 inch display that faces the ceiling.