alt Hacker NewsInteresting they did not go with 2-chip design(1 for main application, 1 for BLE stuff). Which is sometime makes sense because high power mcu usually does not have RF
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The Cortex-M33 core in the SiFli chip will be much faster than the M4 cores that the fastest released Pebble watches used, so a faster MCU than this is not something that's needed. However, more battery life is very welcome, and the fact that they're using MCUs with integrated Bluetooth this time seems to be a huge part of the upgrade from about a week of battery life to about a month of battery life.
It's just a watch. You don't need a full UNIX computer to tell time, or to record heart rates or pinging AWS for those matters.
the more chips you have, the more complex the project becomes. BOM is one thing, every chip needs support passives and oscillators, but now you also need to coordinate communication between the chips, you need to devise a way to update firmwares and access both chips for debugging purposes... that might be worth to trade off for less battery life.
The "high-end" modern MCUs are pretty great, you have the NRF offerings, but also the likes of the ESP32 where you can get Bluetooth and WiFi in a single package.
Personally these days I would lean towards the ESP32, they continue to iterate on it nicely and it has great community support. I'm personally developing a smart watch platform based on micropython.