If there is any incidental complexity, a single additional failure mode of the core alarm functionality then the product is a bad product and shouldn’t even be approved.
Building these correctly is as simple as building a dumb alarm and adding a second product in the enclosure (a radio link). If built correctly, nothing in the smart bit can sabotage the dumb bit. For example, it can have its own power supply. Or be completely isolated from the alarm.
Others in this thread have described how they put an esp8266 or similar right next to their dumb alarm and have it report when the alarm goes off by detecting the sound. This has zero additional failure modes!
The system is designed by a licensed engineering, installed by a specialty contractor, and inspected by the authority having jurisdiction.
Commercial construction is not just like your house only bigger.
A WiFi connected smoke alarm is full of incidental complexity. That makes it inherently less suited to function than the simpler design.