One benefit of fibreglass wings is that they will deform and return to their orginal shape; something that steel and aluminium wings will not do.
This was put to the test at a race at Oulton Park many years ago. I was in second place on the penultimate lap going through Old Hall when I was nerfed then T-boned by another Morgan driver. The force of the impact was taken by my offside front wheel and wing. The damage to my car was a bent wing stay and some cracks in the gelcoat.The other Morgan's front was completely deranged with irrepairable damage to at least one front wing, cowl and possibly the other front wing.
Experience tells me that fibreglass wings are rather more durable and cheaper to purchase than others.