I think you guys are misunderstanding Mirollin91. As you know all Apple mobile products only have a positive and negative power connection to their power supply. The Apple Watch, however, uses magical powers to "beam" power to the device.
So what Apple decided was to experiment with that technology. As a first step they stripped out the ability for the operating system to call the reboot API - so unlike a Mac, Apple TV, iPhone, iPod, iPad, etc the Apple Watch has no ability to reboot. Instead when it needs to restart it talks over the mind-meld to the charger and subconsciously says "I need to reboot". The charger then intensely overwhelms the mind-meld, rendering the Apple Watch unconscious, and the watch is then OFF. Moments later the Apple Watch regains consciousness. Now, as you know, Apple mobile products such as the iPod, iPad, iPhone, etc will automatically turn on when connected to power. Thus when the Apple Watch regains consciousness sure enough it is now booting up.
So there we have it. Now it may seem entirely pointless to even do this, but there's a bigger picture. Apple Watch 3 will have audio stripped out of it. Again, that will be relayed over the mind-meld to the charger and your charger will play the sounds. This is far more efficient because the charger is running on mains electricity so no power drain.
The road map for Apple Watch 4 tentatively shows the next to move is the GPS. A major benefit is you will never lose your charger - however the reason this is a tentnative plan is that it will also mean when jogging you'll be tracked as always being in your bedroom. They're still working on that.
Long term plan is the Apple Watch will eventually have its display shifted to the charger as well, as Apple can get the watch incredibly thin if they do that.