Aero beams are primarily for drag reduction. They are trying to re-attach the flow aft of the tramp and keep it attached forward of the tramp. Attached flow is much less drag than fully detached flow (i.e the wake coming off a round or square beam).

Remember the prototypes on hull #1? They didn't build them there for a reason; CFD is good but modelling separated flow effectively is more of a rare art form than a science at this point. Much easier to instrument your system in a wind tunnel, i.e put tell tales all over your ribbed beam and design the solid beam from there.

Gonna be a fun summer with the AC and C-class action...