Some joints such as the ones in your skull do not move at all. Why do you think it is important that skull cannot move

Because it serves as protection for a vital organ in the body. Also if the skull could move it would make the brain very vulnerable.

If we were able to move our skull it would be very weird.

if you moved your skull your face would look all mest up

in example is your eye sockets they would b moved somewhere else and then where would your eyes go?