I think the concept objective was to make it easier to reef/depower more quickly and effectively than a huge main that many large cruising multihulls have.
I must admit that when pondering 4 years ago about what cat I should build, this design crossed my mind for the same reasons (simple roll system).
I saw also benefits for the back-stays instead of side-stays and the trapeze-wires should also hang more just in the same level as the mast. So the hang on broad reaches should be more comfortable.
Besides that, on broad reaches the sail could act as a genoa with easy possibilities to switch to a full spinnaker.
And for instance also uprighting after a capsize would be much simpler.
But I had too much questions about real-life working and the efficiency of the sail concept and I didn't dare the experiment.