It's the type of song that the koreans usually like: a soft melody that can be considered a ballad. Singers like IU weren't always famous from the start, so it's acceptable that this music can do well on charts for being adorable. Banhana is from the same label as the k-pop legend Nilo, Limez Entertainment. The company use new social media strategies to boost their artists popularity, and it seems to work.
The song talks about forgetting difficult memories from the past.