I didn't follow this project particularly closely so someone more familiar with it can fact check me but I think keeping the art styles was one of the main features when it was announced.
After reading a few works, the art style itself is very important to the impact of things. I hear there have been poor adaptations in the past, and this keeping the original art style I think is a major good start.
It is very Lovecraftian, where the environment is as much or even more important than the actual plot. It creates that looming sense of danger and dread, even if the story is rather mundane in a scene. Just looking at an Ito manga panel now gets my brain primed for something disturbing.
I thought the Uzumaki story itself was ok (perhaps I've read too many derivative works without seeing the original first?) but seeing the art animated really has me pumped for this now in a way I didn't expect.
If they'd manage to keep the pacing right, it'd probably be the most insane shit for years to come. The dad's face at the end is awesome. These painstakingly animated black&white graphics would be a better trearment that what has been done to Berserk with, arguably, a pretty poor CGI work.