It's far far worse than just that. Contacts are abstractions of the core mission of the team. If you're in a contract to push boxes, you reduce your world to boxes. You don't care about accounting, but if account needs something boxed faster they can't just go to the box people because they are in a different contract. So now you have to navigate the bureaucracy... Now it's emails here, and phone calls there. Adding huge time delays to getting something that would would be much simpler if they were on a unified team with a unified mission.