It's surprising that they'd heavily line a linen suit when they do a number of seersuckers that are properly unlined/unconstructed such as this Cambridge
BB knows that the person buying their traditional seersucker suits and jackets is not the same person buying the pink linen costume suit.
I just stopped by the BB around the corner from my office, the Gatsby linen stuff is very overbuilt. Admittedly, the example I looked at was well put together and will probably last quite a while. That if you tried to wear it to an outdoor cocktail party in August you would probably end up with heatstroke will be lost on those who will actually buy it.
(P.S. Saw the movie - was better than I expected given the reviews.)