Absolutely right. There is no way that a Cortex-A series processor will be as efficient as the Cortex-M's microcontrollers that are being used by the Pebbles.

Absolutely right. There is no way that a Cortex-A series processor will be as efficient as the Cortex-M's microcontrollers that are being used by the Pebbles. There is also nothing that needs the power of the Cortex-A's either, the M series are perfectly capable of doing everything a watch needs to.