Android Wear USB Hardware Connection/USB Power Question topic

On android wear watches with USB ports on them (The Samsung Gear is the only one I've found so far, but I'm sure there are others), can the ports provide power? Also, are there any restrictions to interacting with/accessing a device that you plug directly into your watch? I imagine if you write an app for it, you can interact with whatever hardware you plug into the watch, correct?

Sorry if these are obvious questions, I'm by no means a developer.