Some interesting ideas, have to see if it gains traction at all outside of China.
HarmonyOS started life as a TV OS, to create opportunities for seamless casting and fluid movement across devices, so a user could be on a video call on their phone, cast it to a TV in the kitchen, then continue it in the living room. After that, they could take a phone call, moving from room to room, with the call following them around jumping from one smart speaker to another.
A new Task Center feature also allows you to use apps on different devices without having them installed on each one. For example, you could play a game on your smartphone and then transfer it to a HarmonyOS tablet without having to redownload the app