Welcome to the uncanny valley.
Want to know a big reason why the uncanny valley occurs that could be fixed in 10 seconds?
Face symmetry. Animators generally make one side of a face and flip it to make a whole head, its takes half the time and its looks pleasing in some ways because symmetry equals beauty in many respects. The problem is our little monkey-brains are smart and can sense symmetry that is too perfect instantly.
If you look at the video of the actual girl and measured her face you'd likely find here face was somewhat non-symmetrical. But just from the picture you have in the bog you can see the animated girl has a perfectly symmetrical face.
It would take about five seconds to make the face mesh non-symmetrical and another five to adjust the ‘skin’ over the mesh to be somewhat non-symmetrical. Move an eye up a millimeter, make an ear stick out a bit, adjust the size and shape of the nostrils a bit, and in no time the animated model would look a bit less perfect. That alone would make the video somewhat more convincing, but would also likely make the video uncanny in other ways.
I don’t recommend this because it maybe depresses you, but it will be informative. Put a camera on a desk. Put your chin on the desk lightly (don’t squish your chin) and try to hold your head upright and straight. Take a picture. Put the picture on a desk top art program and draw a straight line from pupil to pupil. Using the reference see how un-symmetrical your face is when in isolation. The fact is many people have extremely unsymrical faces and that just one way of looking at you face there are some features on peoples faces that are symmetrical, but they are odd like a chin the is forward of the upper face, or your eyes being too far/too close together. Real people are often non-symmetrical because were organic…and shit happens.