I have a camera but it's for outside only. Personally wouldn't have a camera on the inside, cause I had scuffles in the car years ago, and get a few punches in.
I remember a lad sitting in the passenger seat, reached over me to grab something(phone or money). Anyway, got him in a headlock and punched the head off him. He got out and legged it. Would rather not be caught in my car for that.