But Siwan is most known probably that's why, and If I remember well, we knew about him cast first then YeoReum…
u don't know who Seolhyun is right? because otherwise you wouldn't say that Siwan is more known. and if you read the manhwa, you would know that Summer (YeoReum) is the main character while Daebom is more like leading male character
“I Don’t Feel Like Doing Anything” (literal translation – previously titled “Summer Strike”) is an upcoming Genie TV original drama based on a popular webtoon of the same name. The romance story is about people who decide to quit their current lifestyles in the busy city and move to a small town to do nothing, where they’re ultimately able to find themselves. source - soompi
source - soompi