A backup camera is more than a convenience. It gives you visibility that you simply cannot get without it. Unless the rear half of your car is transparent, every time you back up you do so with a blind spot directly where you're driving. There's a reason these cameras are mandatory on new builds.

Yes, but less safely. Hence the mandate.

Modern vehicles have very high belt lines for crash safety, but that also makes for even larger blind spots.

The flashing at full brightness, then dimming, then brightening again before rebooting isn't exactly fun at night.