Wallace Berry wrote:
What makes this structure
lighter or cheaper or easier to build than conventional wings?

Who ever said the generation of gliders would even begin to consider
the idea of cheaper??? That has not been the recent trend.
If it is lighter, it appears that the concept is to spread the wing
load over a much wider area [more of the chord], so that the stresses
do not need to concentrate on a single heavy spar. The wing skin can
possibly be made thinner/lighter this way too since it does not have to
transmit the load as far.

Chris