Repurchase/loyalty
A very large share of reviews are 2nd-6th+ bottle repurchases, with several users stating they have used it for years (some citing 4-10 years) as their long-term holy grail moisturizer.
Ingredient/brand trust
Reviewers frequently cite trust in the COSRX brand and its oil-free, birch sap-based formula as a reason for buying, saying they trust anything COSRX releases.
Suited to oily/acne-prone skin niche
Many buyers specifically sought an oil-free option for oily, combination, or acne-prone skin after other moisturizers felt too heavy or caused breakouts.
Gifting
Multiple reviewers purchased it as a gift for family members (mom, son, husband, partner, grandson) or included it in a skincare gift set.
Price/value
Several reviews mention it being affordable, cheaper than alternatives, and good value/CP for the formula and bottle size.