Cotton keeps you cool. Linen keeps you cooler. This shirt blends the two so you get linen's breathability without the "just pulled it out of a suitcase" wrinkle factor.
Short sleeves, a relaxed but not sloppy cut, and a texture that photographs well — which matters more than people admit when half your summer ends up on a camera roll. Works solo on a hot day or layered under something lighter in the evening.