Hi @UE_FlavienP ,
I understand more on the topic now. There are so many ways that we can utilise to export Rhino files and it is so flexible. It is amazing. However, I hope that the documentation should include some of these explanations so that users can make the right choice when it comes to choose the export for the job.
Our projects handle very large geometry files with thousands to components sometimes. Because of this, I need to develop an export workflow that is suitable for our team usage. By the look of it, I may need to experiment with the udatasmith export as well.
By the look of it, the UE4 documentation have not update the fact that it can import 3dm files directly!
Datasmith Supported Software and File Types | Unreal Engine Documentation
Thank you very much on the detailed explanation. 
