Maybe use of the word is more about drawing attention. If something is said to be sexy, then people will want to see it.
Recently, someone told me one of my book covers was sexy. This is why I'm pondering the question of "sexiness" today. Here's the book cover; judge for yourself. Sexy or not?
I'm grateful for the comment, but it still baffles me. When Pineapple Press helped me compose this cover, we weren't thinking "sexy." We wanted to project the idea of the lighthouse as needing a keeper to bring it alive. But maybe it turned out sexier than we intended. What do you think?
Lighthouses can be sexy, I suppose...in a subtle way. They certainly add to the milieu of sea and shore and make it prettier and more interesting. The seashore itself might be sexy in some ways. Lighthouses are interesting background objects in seashore photos and images. Postcard manufacturers and photographers know this. Check out these pictures from various websites and see if they are examples of sexy lighthouses: