I finally found a clear answer to this question.
> FME & Esri ArcGIS Data Interoperability FAQ
Can ArcGIS Data Interoperability run my existing FME workspaces?
No. ArcGIS Data Interoperability cannot run existing FME workspaces. If an FME user has workspaces, they will have to recreate the functionality of their existing workspaces within ArcGIS. This may or may not be successful, as the ArcGIS Data Interoperability extension doesn’t contain full FME functionality (see next question).
Note: It is possible to copy and paste transformers and data models between workspaces made with FME into custom tools made with Workbench inside of ArcGIS.
So, when I need to transplant an existing workspace to ArcGIS Data Interoperability, I have to re-create that in the ArcGIS Interoperability environment or copy & paste all the items of the workspace. However it may not be successfull because there are formats or transformers unsupported by ArcGIS Interoperability.