Groups can benefit from leaders leading their meetings, particularly when the group is new or dysfunctional and the leader is a capable facilitator. Otherwise groups don't need leaders and in some contexts do worse with leaders who lack facilitation competencies. Groups can develop, even in short periods of time, a natural ability to self-organize without the need for a leader.
It's my experience that as long as a group has what's called a liberating structure, like the Agile Canvas, it can easily self-organize even as a new group, with diverse perspectives and with fairly complex tasks.
