Team is a perfect tool for collaborative work under apps development. The team could be an IT-dept of a company or an agency (or a group of freelancers).
Each developer seat in a team is equipped with a Pro-sandbox slot for an app. Pro-sandbox plan is a fully-functional plan, perfect for app development.
When app development is completed, it can be delivered to a client, keeping the connection with the team, thus:
the developer will be possible to support the client, having an access to an app;
the developer will get his share of clients' license payments.
My teams section is available from the home page. Team admins are able to add developers, edit the team, create Sandbox apps.