We've already seen a short video where Android Wear is used to do simple things like toggle lamps and open a garage door, but Armando Ferreira took that concept and applied it to all the things. In this video demoing home automation with Android Wear, he toggle lights, a popcorn maker, and a PC, but doesn't stop there. He also uses his G Watch to adjust his home's thermostat, turn on the TV, and get a notification if any of the doors or windows in his house are opened. It's pretty nuts.
The only "downside" to this is the lag. Google still has a bit of work to do with AW's response time, as each command takes a good 10 seconds to execute. In an ideal world, this would be cut down dramatically...but we'll get there. It's still really freakin' awesome (and useful) nonetheless.
It's not entirely clear what he's using to execute all these commands, but he mentions Tasker at the end, so I'd assume it's the same stuff we saw in the other video (on the phone side, at least). Update: He's using Tockle, as noted in the comments below.
Anyway, if you're looking for more of a reason to justify buying an Android Wear device, Ferreira just made it a little bit easier.