This volume is extremely important to read if one wants to understand the White Room better. A lot of details about Ayanokouji's childhood is mentioned for this volume, giving the reader a new perspective of Ayanokouji behaviours. It also gives an insight into the White Room, the organisation as a whole and Ayanokouji's father. Most questions I had about the White Room were answered with this volume. It was also interesting seeing how Ayanokouji's father behaved since he is usually only seen as powerful and heartless. While the main focus was on Ayanokouji and his father, the other White Room students like Shiro but also Yuki werepart of the story too. These characters made it able to see Ayanokouji in a different light, before he started school at the Advanced Nurturing High School.
I wouldn't recommend reading this before actually starting the series as it's an addition to the story and it's understood better after already knowing the characters. I personally read it after finishing the first year of the light novel series.
If one already knows about the characters and the plot of Classroom of the Elite then I would definitely recommend this as it's not just a simple addition, but something that explores Ayanokouji's character and makes the reader understand the White Room faculty better.