Others have called out how this will impact politicians and law enforcement. On a slightly different note, how many voice actors have recorded twenty minutes of dialog in the past? How many of their contracts give them control over how the movie studios use those recordings or mandate that the studios give them royalties for using "remixed" versions of their voices?
For example why pay (a bunch of money to) Mark Hamill to provide the voice for a new animated version of the Joker when you can use this tool to put Hamill's words in Joker's mouth by paying (a lot less) money to Adobe?
And if the tool becomes good enough, why not "find" a "lost" Freddie Mercury (or $YOUR_FAVORITE_ARTIST) recording that he never sang? It may sound exactly like Mercury, but the recording industry will argue that it's different enough that they don't owe Mercury's estate (or $YOUR_FAVORITE_ARTIST) anything.