Private/internal repositories limit package access to authorised clients and users, without sharing packages to the world. If you need internal software distribution mechanics, or if you want to support license-based software distribution, then private repositories facilitates these.
Collaborate securely with other users in an organisation with no per-seat pricing - In other words, there is no limit to amount of users/seats within an organisation (and no limit to number or size of teams).
Granular Access Controls
Add granular access controls to your repositories and packages to give appropriate access to collaborators or teams within your organization. Need read-only access for junior developers or one single repository for contractors?