I think it is a neat product with two strange limitations that I can't quite figure out:
1. No apps. This would be perfect for my kitchen but I like to watch videos, movies, tv shows while I cook. The aspect ratio is not ideal, but the fact it won't support third party apps means that is not an option. Maybe it will support Airplay video and I can cast from my phone?
2. No battery means it is stuck to the wall. They had to work around this limitation in their own (excellent) promo video by drilling a hole in the middle of their kitchen island. The device would have a lot more utility if it could be moved around a lot and then say in a base station like a Sonos Move.
From the product website:
"Additional apps. HomeView supports compatible third-party audio and video apps from your iPhone for a familiar experience across devices."
If I had to guess this would be kind of similar to the way CarPlay supports apps, but it's admittedly possible this just means "you can use AirPlay yaaaay".
As adamesque wrote, it's going to be more like the Watch or even CarPlay. And I think this is probably the right approach, market-wise: Apple ran with the idea that every device needs its own standalone app ecosystem, to the point where they even tried putting an app store in iMessage, and it didn't really work out. Apps on the Apple TV that aren't effectively "channels" (i.e., streaming services) have mostly fizzled, and I bet most readers even on Hacker News forgot that the Watch even had a standalone app store for a while. The HomeView absolutely seems like the kind of device that's going to do better with "companion apps": install them on your phone and let them install a little mini-app or widget on the HomeView. I don't need to manage a whole new set of apps on my smart home gadget---I just need to be able to futz with lights and the thermostat, listen to music and podcasts with the music and podcast app of my choice, and get to my recipe app if I'm going to be one of those monsters who puts one in the kitchen.
As for the battery, this doesn't look like a kind of device that's intended to travel with you room to room---but I agree it would have been smart for them to give people the option.