If it's mains powered, there's your opportunity to fry everything during the same episode that's likely to start a house fire (if not from the actual fire alarm

If it's mains powered, there's your opportunity to fry everything during the same episode that's likely to start a house fire (if not from the actual fire alarms bursting into flames in a fit of cosmic irony). If they're linked by radio, hopefully the circuitry is independent of the operation of the basic "detect smoke -> make noise" circuit, so for instance, when your radio shorts out, it does not blow out the power supply to the detector and noise making mechanism. Yeah, it's too hard to design this to trust that commercial options are safer than dumb alarms.