In my new story Splinters I sometimes use 'full-page' illustrations. I like to focus on the emotion, action or person that is important at that moment in the story. I decided to bring in some variation in the lay-out of the pages by using one drawing to fill a complete page with. It also shows the reader that something important is happening, or that, for instance, a new day is starting or that they're going back in time.
It's not something new. Of course other artists did it already in the past, like Craigh Thompson in Blankets. I think it can work very strongly and can bring a lot of drama if you do it in the right way and and at the right moments.