Also if you read the novel you'll truly realize how important this is lmfao
What's the reason
Okay, it's minor spoiler
It's been pointed out every now and again that Gye Yoon has a big and tall stature that he could easily tower over everyone else, including Wonwoon. He even used his build to intimidate those who showed interest in Wonwoo by sticking close to him like a shadow. Not only that, it's textually confirmed that he has a great bod that even his brother-in-law praised him for it twice; first was when he talked with Wonwoo, and second time was when he defended Gye Yoon's honor (and sex appeal lol)
Ahaha that's so entertaining can't wait for it to be drawn xd
Really love how the artist decided to draw shirtless or naked Gye Yoon for no reason at all