The Management API and Gaia API are used for different tasks.
Depending on what you are trying to do, you may use one or both.
Ansible only allows you to describe the desired end state of the configuration of the overall system.
Ansible then calls the native Check Point APIs in the appropriate order to achieve the desired configuration.
The native API calls allow you to prescribe the exact steps needed to achieve a desired configuration.
However, you must know the precise order to call the APIs to achieve the desired configuration.
The APIs do allow for things that cannot be described in the Ansible framework.
I hope that makes sense.