I can't get this feature to work at all. I installed the Google camera to use the selective focus feature, but that is really fiddly and blurs areas that should be focused and vice versa.
Personally, if I want a bokeh effect, I use After Focus. If the software makes mistakes in the camera mode, there's no way to fix it. With After Focus, I can add bokeh to any normal picture. I use it on my Note Pro because of the SPen and the ability to see more detail.