Acne-prone skin targeting
Many buyers purchased specifically because they have acne-prone, oily, or hormonal breakout-prone skin and were seeking a dedicated trouble/spot serum.
Repurchase/loyalty
A large share of reviews are repeat purchases (2nd–10th+ bottle), showing strong reliance on the product as a skincare staple.
Word-of-mouth and social recommendation
Several reviewers mention buying after seeing it recommended in Korean videos, by friends, or due to its reputation/hype ('Korea's 3-day serum') among Olive Young shoppers.
Value bundle (refill + spot gel)
The refill pouch and bonus spot gel included in the set were cited as a reason to buy, offering more product for the price and encouraging continued use.
Gifting
Some reviewers bought it for family members (children, husband, mother, teen daughters) dealing with acne, suggesting gifting/family-use occasions.