The best type of team is one that works well together. For people to work well together, it’s best if they know and understand their counterparts. It’s possible for people that only know each other by name to be productive, however, they are unlikely to be as productive as if they knew the nuances of each other’s skills.
A well-functioning team is extremely difficult to build. It takes time, effort, and money to put it together. You need people to separate themselves from their normal jobs and come together. As a leader, you need to value the effort and sometimes force the issue.