A strong bad publicity removal tool for the midgamewith low influence. For the cost of a click and 2 per BP, you can remove a large advantage for the runner. By combining two BP removals into one card, the Corp saves card space and gets essentially the same deal as a runner to remove tags.
Leave the witnesses alone unless you know the runner is Valencia Estevez: The Angel of Cayambe with Investigative Journalism or, more likely, your deck is rolling in BP. GRNDL: Power Unleashed loves this card, especially after scoring some Hostile Takeovers or Geothermal Fracking. You do not want more than 1 or 2 of this card in your deck, this card will be a useless draw if it's drawn too early.
Have fun with the witnesses!