If they did zwave they'd have to be part of the alliance and compatible with other hubs. Going zigbee frees them from that.

Rob, I can't swear, but I don't think that's the case. They have to be CERTIFIED for interoperability, but that doesn't necessarily mean they have to "support" every device. Most of the Z-Wave-enabled hubs support only a heavily curated list of devices.

I'm going to have to figure this out.