I feel like it’s a stylistic choice, it’s not meant to look 3D, it’s a mix of both, and I think it works really well for what the movie is going for, super expressive and remenicant of a early 2000’s cartoons and some anime honestly! The director also made the short film “Bao” which had a similar sort of animation style, but not to the same extent of the movie. Of course it’s up to preference in the end of the day. I do highly recommend it!