'artistic' or 'aesthetic', maybe, for the second one?
Like you, I tend to see efficiency as most beautiful, especially when one simple structure fulfills several complex requirements simultaneously. A tiger or a gazelle is beautiful because it's very close to optimal for the niche it's evolved to fill.
I dunno but maybe it's the equivalent of countershading camouflage? Tigers are ambush predators that attack from above. If a tiger's fur only accounts for a small percentage of the sky above you, and orange and blue are complementary colours, then small bits of orange fur plus blue sky shouldn't stand out.
Like you, I tend to see efficiency as most beautiful, especially when one simple structure fulfills several complex requirements simultaneously. A tiger or a gazelle is beautiful because it's very close to optimal for the niche it's evolved to fill.