Teams involve more people, thus offording more resources, ideas and energy than would an individual.
Teams maximise a leader's potential and minimise her weaknesses. Strengths and weaknesses are more exposed in individuals.
Teams provide multiple perspectives on how to meet a need or reach a goal, thus devising several alternatives for each situation.
Teams share the credit for victories and the blame for losses. This fosters genuine humility authentic community.
Teams keep leaders accountable for the goal.
Teams can simply do more than an individual.