The multiple points of view contributed to giving a more complete picture of what was going on, especially with respect to the progression of Anna's dementia. While reading one point of view questions and objections would come to my mind which were then addressed when reading another point of view.
My mother was diagnosed with Alzheimer's disease about three years ago. The different points of view in the novel pretty accurately represent the differing perspectives in my family on topics like sex and love between people with dementia (my mother is in her 80's, but this still came up!), how to communicate with someone who has dementia, and what is the best thing to do for someone suffering from dementia.