The dashcam market is well developed, with the only real issue being you have to run a USB cable in your car to power it. I don't think this would add enough value over the ones you stick to your windshield.
For instance, I have this one; it's very small and not likely to get stolen:
A backup camera would be great, since my car doesn't have one and there are kids living next door, but my OBD port is already in use by another tech gimmick…
For instance, I have this one; it's very small and not likely to get stolen:
https://www.amazon.com/dp/B00UUS52YG?psc=1
Hasn't gotten me anything yet but I hope to get Youtube karma someday.
On the other hand, this product does add value, it just happens to be evil:
https://news.ycombinator.com/item?id=11934455
A backup camera would be great, since my car doesn't have one and there are kids living next door, but my OBD port is already in use by another tech gimmick…