For better or worse, a huge amount of our justice system depends on eyewitness statements.
For example, if my crazy neighbour knocked on my door, pushed their way into my home when I answered then beat me up - the only evidence of who did it would be my eyewitness testimony.
There would be incontrovertible evidence that someone had assaulted me, in the form of my bruise-covered face and body. But only eyewitness testimony as to who.
With the current justice system, that would almost certainly be enough for a jury to convict.
There are tragic miscarriages of justice from time to time, and certainly DNA evidence should be used whenever possible. But would I prefer to live in a world which rejects eyewitness testimony, where a crazy person can barge into my house and beat me up with no consequences? Or a world where I have to have CCTV in my own home? Not really to be honest.