This is an interesting option to try (I have a Pebble watch, so battery life is not an issue). The theory is that raising the wrist normally kicks the full CPU on to check time, and that probably triggers quite a bit when you don’t want it to.
Turing off the raise wrist activation, but also enabling AOD, could result in less battery usage.
I suppose this may differ between watches and people, so it is something one needs to try and see what difference it makes. The theory could make sense though.