While it may be an overstatement to say that teams always add value and benefit to organizations, it is certainly true that teams that have been put together well and used correctly do add value. The reason for this is, generally, because of the fact that teams allow collaboration between a number of people.
The benefits of teamwork stem largely from the facts that there are many people on a team and that those people interact a great deal. Because of this, a team is often able to generate a wider range of innovative ideas than an equal number of individuals working alone. The team members can also discuss these ideas among themselves, which allows them to improve on the initial thoughts. These facts mean that teams generally bring about more innovation than individuals do. In addition, the various team members will bring different skill sets and personalities to the team, allowing the team to be versatile.
Another benefit of having a number of individuals working closely together has to do with motivation and morale. Working with a team can give an individual a greater sense of purpose and of belonging. When individuals feel this way, they will often have greater motivation to work hard because they feel good about their work environment.
For all of these reasons, well-made teams can add more value to a business than individuals who are working alone can.