Regional operators that want national coverage, out-of-coverage factories that want their employees to be able to use their normal devices, and greenfield MNOs that want a bridge to a national network – these are all use-cases for hybrid networks.
Create simple networks with national roaming and your own network coverage. Then, when the user moves out of coverage of your own network, they leverage national roaming with one of the national operators. Implemented correctly you can create a consistent user-experience across the various networks, leveraging both the traditional telecom services like voice and messaging, and more additional functionalities such as mobile switchboards.
Hybrid networks can quickly become prohibitive to implement in terms of both cost and complexity. Taking a platform approach where users can move between designated access networks removes large amounts of complexity. In addition, offering a pre-integrated platform and the ability to scale up to the use of public networks, while handling the smaller scale regional/private networks makes this complex offering simple and affordable.