The practical value of video runway surveillance at airports has been known for decades and has been (pretty sure about that) recommended by crash investigators. Even if it hasn't, the benefits are still pretty obvious. A few cameras on the control tower would do it, with infra-red for nighttime. It could be used by airlines to monitor landings, enable analysis of RTOs and go-arounds, minor collisions on the ramp, etc. etc. And that is before stating the obvious value in a crash investigation on or near the airport (about 70% IIRC of crashes are within a mile of the tower). And in the US there is a lot of worry about land and hold short, and about potentially disastrous on-ground collisions and runway incursions. Video would help analyse all that.
The reason they are not installed is because if any such images became public it would be bad
PR for the airport and the airline.