"Because it's there," is one answer a mountain climber might give. But it's also a reason for a quick knitting hat like this. The laptop sleeve (the one I haven't yet written the instructions for) was finished, but I had most of a skein of the Noro Silk Garden, and a full skein of the black contrast yarn.
I used the instructions for Flory's One Skein Noro hat, which I've used many times before - basic, easy, and open to creativity. The Ravelry link is here. I changed the sizing a bit, and made a garter stitch edge where the original has a rolled knit one.
I really like this color-way of Silk Garden. I finished this hat in a couple of days, but that included several false starts on the striping. And though it was blessedly cool in Newport (Oregon, not any of the others by the same name), it wasn't cool enough for wool caps, even if the wool is mixed with silk. And yes, we did see whales, almost every day we were there.