True. There's a lot of mystery surrounding the plans for their hub. But they've introduced a beta of local control, so depending on how open their API is will tell what's possible. I have Ecobee (You should be buying Canadian eh? ), and Wyze for the cameras. Really all I want from a smoke and CO detector is for it to work and not give false alarms.
The fact that it can notify me and turn on my lights, and light my way at night, and not over react to steam, and not make me change the batteries every year, can turn off your nest thermostats without wifi working, and sends me reports, and tests itself !!!
These things alone are incredible. But then it also gives you a little green wink before you go to bed . Interconnects without wires (very important for me in house built in 1926), and it's excellent industrial design, comes with amazing screws, nice packaging, and they cost $150 CAD before tax. My only complaint.
I have an Aqara natural gas detector on order, That post of the house exploding was a call to action for me. The Aqara Hub HomeKit edition I bought is ETL Intertek certified, even though it came with a Chinese plug and an adapter. So I'm sure the Gas, and the smoke/CO detectors are as well. Have you read anything about false alarm rates being an issue with the smoke/CO? I could use a few extra and don't need that many nests at such a high price. Do the Aqara smoke/CO detectors interconnect with themselves? Haven't researched them at all.