Brand trust from other Round Lab products
Many buyers purchased because they already loved Round Lab's Dokdo cleanser or Birch Juice cream and wanted a matching gentle cleanser.
Free/bonus cream in the set
Several reviewers mention buying because the set included a travel-size moisturizing cream, which they saw as good value or a nice bonus.
Recommendation for sensitive/reactive skin
Reviewers with rosacea, atopic dermatitis, or damaged skin barriers sought this out specifically for its reputation as non-irritating.
Repurchase / loyalty
A large number of reviews explicitly state this is a second, third, or ongoing repurchase, indicating strong repeat-buy behavior.
Gifting
Multiple reviewers bought it as a gift for daughters, husbands, sisters, or friends, citing its gentle, broadly suitable formula.