"Graphic memoirs are comics or sequential art that tell an autobiographical or semi-autobiographical story...
Most graphic memoirs do not cover the same wide scope a print memoir would. Typically what they lack in breath, the make up for in depth. Since graphic memoirs are instead more focused, they often afford the author the opportunity to focus on one particular event, span of years, or relationship with someone or something and their feelings surrounding it. A key advantage of using the comics medium is the ability to show rather than merely tell. Everything from the font used for a particular character’s speech, to the size and position of each panel helps to tell the story. In memoir, this can help the author to communicate a feeling or situation from their past more immediately and, and perhaps more effectively, than if they were relying on text alone."
http://www.yalsa.ala.org/thehub/2015/02/16/genre-guide-graphic-memoirs/