People will break your window for spare change, an empty envelope, or your stereo. Old phone or dashcam? They'll steal both of those too. Tons of old Android phones around, too, plus the folks that mount their current phones in a dash holder every time they get in the car ANYWAY, so why not have a "free" dashcam running. Plus, for those that want cloud recording, TinyCam has lots of different options.
I haven't tried it yet, but I wonder if a TinyCam Android dashcam with FTP enabled could automagically sync all recordings with an FTP server when it returns "home" and connects to wifi? File that under things that make you go hmmmmm...