If you're going to be taking a camera with you, you might as well as carry a phone instead, since every camera I know is a lot bigger/thicker/have worse battery

If you're going to be taking a camera with you, you might as well as carry a phone instead, since every camera I know is a lot bigger/thicker/have worse battery life than any cell phone. Alternative would be a Snapchat glasses or the discontinued Google Glasses, which have lower-quality image and the added bonus of looking dorky in appearance. EDIT: Forgot about GoPro Session or those miniaturized action cameras (such as Mobius and Polaroid Cube)