One big problem is going to be that political supporters have been more than willing to assume anything they don't like about their candidate is a "deep fake", regardless of the fact that this has only been a recent possibility. You could have an authentic video of their favorite candidate telling everyone how stupid their supporters are, and those supporters will never believe it (or vice-versa, that easily-detectable fakes are made to smear a candidate, and the opposition will gobble it up).

Yeah we're going to see a lot of disgusting stuff like fake porns, but that was already being made on still photos so of course we're going to start seeing videos now. I think it will be interesting to see what happens in Hollywood, where actor's voices are already being used without their consent. If laws get passed to discourage such things (and we've just seen the FCC ban the use of faking politician's voices), they can also be used to curb other fakes of real people. I think that will help, but in the meantime it's still the Wild West of AI-generated content.