Altering primary documents to make them more palatable to modern audiences is great for emotional engagement and attracting attention, but it risks creating false impressions of what history actually was like and how we know what it was like. "Hamilton" is a powerful piece of art--today--but it's not accurate history in an academic sense.
(Well, I should say it's not history of Hamilton's time. It will be studied as an important part of the history of our time.)
The folks running these upscaling operations understand the concerns:
> Antic and Kelley aren’t under any illusions that images treated by DeOldify will come out historically accurate, though their reservations are with the practicalities of training a neural network. Making sure colourised films are accurate is “a literally impossible problem,” Antic says. DeOldify uses modern images to train its AI on, he explains, “and we know that's a big weakness, because, amongst other things, it biases people to wearing blue jeans.”
The challenge is, once they create one of these films and post it for the public, the implications and effects are out of their hands.
You might have millions of people watching an AI-changed film and think that what they are seeing is more accurate than the original, since it transmits more information (detail, color, etc). But if that additional information is made up, it's actually not more accurate, and maybe actually less accurate (e.g. wrong color instead of no color). That nuance is going to be hard for a lot of people to understand.