The article says brainstorming is popular for both good and bad reasons, Its a group activity involving the pursuit of new ideas . The good reason is that a typical brainstorming session brings people together into the creative process, and increases the social nature of the project. Every member of the group contributes by giving their idea to what they will be working on in the future. It is a bonding experience where people starts thinking and communicating with each other about topics relevant to the next few weeks or months of work. People have some shared questions and ideas to discuss over lunch, in the hallways, or at drinks after work after the brainstorming session. Something more valuable than the brainstorming results itself is the side effect of injecting something interesting and meaningful to talk about into the team culture. The best ideas might come not only from the big brainstorming session but also from those side conversations. The bad reason that you get too many ideas and people get divergent, if there is not someone who can converge those ideas, then its not useful.