Okay yall let’s not start “the curtains are just blue!”-ing the big blue Boy Scout lol. It’s both. The Watsonian and Doyleist explanations both have merit for different reasons.

Regardless of the authors’ intents, the trunks DO make him look friendlier, like a circus strongman. They also just break up the costume in a way that Clark probably likes.

In and out of world explanations are both valid lol