What is the importance of the tattoo Gerta receives in Auschwitz in the graphic novel, What the Night Sings?

At Auschwitz, Gerta was given a unique identification number that was tattooed into her arm. When the British liberate the camp, and Gerta is asked for her name, she shows her arm. This symbolizes how the Nazis took away the prisoners’ identity and rendered each person into just another number.