It’s going to get to the point where you can’t even say in a court room “well we have video of him doing this”. The fact that deepfakes will exist will erode confidence in even those things that are true. At the same time it will add additional fake situations to the conversation.
Worst part is that eventually even the AI-powered counter measures are going to fail eventually. The moment a computer knows what gives away a hint that it is a deepfakes and not real, a computer can solve to not present that give away. The “good guys” and “bad guys” will iterate with each other until it is perfected.