In Julieanne Kost's video Focus Area seems to work well on her example with the subject photographed against a solid color background. When I tried to use Focus Area on typical photos, it did not work to the point of being useless. Further, it caused random patterns to appear on the photo which could not be removed with any selection process, and required shutting down Photoshop on my Windows 8.1 (i7-4930, 26gb ram nVidia GT640) machine to regain proper operation.
Is the new Focus Area working for you?
Works fine for me. Upload one of the images you tried it on.