From my perspective the Pros are:
Aluminium front beam always remains in tension so is not subject to cyclic bending stress loading through it's neutral axis and therefore lasts longer.
There is a slight inward camber on the centreboards which may provide an increasing lift force when heeling and flying a hull.
This may also be transferred to the rudders if they are aligned with the centreboards.
Front beam and rear beams are not perfectly aligned so there is some induced stress through the hulls when the rig is tensioned. Either way with positive or no camber there will be some stress induced but the hulls are sufficiently strong enough to cope.
These may be just ramblings of an idle mind but hey isn't that why we have forums; to get ideas out there for discussion.