This is a useful visual explanation of how 3D CGI fails to capture the look of traditional animation.
In animation you create key poses which are then inbetweened. As in this example by Preston Blair, the key poses are supposed to be very clear with strong silhouettes and staging, which may be cheated a little (or a lot) to look good from a single camera angle.
CGI animation often lacks that clarity of staging, because these are 3D characters constructed to make sense from any angle. It's possible to warp and cheat them to move in a more stylized way, but this takes a lot of effort, rather than being built into the process in a drawing.