Plugging an Animation Sequence directly into the Final Animation Pose without using a Pose Blender will not automatically apply the curve driven animation.
Additionally, using only a Pose Blender node without supplying any incoming curve data to drive those poses will not output your desired pose.
You will need to use a method to drive the curve data along with the Pose Driver node to effectively manipulate the final pose.
You can also convert a Pose Blender to a Pose by Name (or a Pose by Name to a Pose Blender) node through the right-click context menu.
The Pose by Name will enable you to manually specify which pose to use inside the Details panel that is used inside the Pose Asset.
For our example, we are controlling two aspects of our character's face, the right side of a smile and the left side of a smile, therefore, a Pose Blender make more sense to use.
If we wanted to control only one pose within our Pose Asset, the Pose by Name provides the ability to control a single pose by its name (which is usually good for full body context).
If you are using a Pose Asset with Additive enabled, you will also need to use the Apply Additive node to correctly display your desired pose.
For Pose Assets that are not Additive, you can directly link a Pose by Name node to the Final Animation Pose output.