Most of the time they are up in the black area of the window behind the rearview mirror with just the lens showing and the wiring is ran in the roof liner, so they are not that noticeable. Some popular model cars even have aftermarket you can buy that part of the rearview mirror.
Plus many have LTE and GPS that will send back video of any movement, so a perp will likely not take the chance that it is doing that and provide clean video and location of them LOL.
I had someone fail to yield at a roundabout and I smashed their B pillar in.
My wife had an officer change lanes, into her lane, mid-turn, and she had to pass him to avoid collision. He pulled her over and she had to convince him he cut her off, mid-turn.
I was on a jury for a trial where dash cam footage would have answered all of the questions and not wasted my time.
I had a tractor trailer run me off into the center shoulder twice and then proceed to drive like a jackass, doing the same thing to other cars and semis, for 20 miles.
I have one in the motorcoach. Mostly since cars seem to think that you can stop on a dime and do like to cut you off. Have not had an actual highway incident that needed it yet, but have recorded a lot of things seen on the road with it, like one guy's rear tire coming off his car and passing him. The first one I had in there was stolen when they broke into the RV at the storage yard. Since then, I remove it when it is in the storage yard.
Keep thinking I should put one in each of my and wife's cars, but have not done that yet.
25% of the crashes around central Florida are hit and run. Anything to help you get ID and license plate info is a big plus. I was involved in a sandwich wreck where I was in the middle while at a complete stop. The persons insurance company that my truck rear ended, tried blaming me for their damages. I told them I had very good dash cam video of what happened. Never heard another peep out of them. Get a dash cam with rear window cam also. They work!