Whole issue of fake media and that, well, look at social media over the years, I doubt it will make much difference than what we have already. People over time, learn what to trust and who to trust.
The real issue though, as you touch upon, will be governments using this as another way to gain even more power and control of our daily lives.
Though my thoughts are, like most new tech that can copy/mimic - it will be the Disney's and movie studios with their lobbyist money that will do the most harm in any progress.
Though mindful of the potential damage, a rouge AI could do in the financial markets.
One upside - postal letters will start to see an increase in usage as people start to trust physical media more over digital. Is certainly a trend I foresee happening.