Moreover, there is no way this watch is pulling over 24 hours battery life. They said that they expect you to charge it everyday. In that sense, the power should not be much of an issue as big as the comments here presume. LG G Watch easily lasts 24 hours, and Moto 360 easily goes 16-20 hours. So unless this watch lasts 2 days or more, screwing up the UI makes little sense, you'd be charging it every night anyway.
It does use an OLED display and we know black uses less power.