I like a good smart watch and I appreciate open source, but an ESP32 isn't a great pick when low power consumption is important and the device is going to be communicating regularly. I'm surprised LILYGO went that direction in a watch form factor.
An advantage of ESP32-S3 could be that it seems possible to run Linux on it.
Most of their lora devices are ESP32.
an esp32 on an 1100mah battery will last years on deep sleep, and about a day with wifi on and in high power modes.
a pixel watch 4 says they last 30 hours , ambiguously. they use a battery less than half the size. in reality with constant use they'll drop dead in 6 hours.
the thing is clunky and heavy , anyway -- so if it lasts as long as an off the shelf watch who cares?
also, the primary reason : lilygo shoves ESPs into everything.