Deep discount / flash sale pricing
An overwhelming number of reviewers explicitly mention buying because it was on sale for under 1000 yen (or ~$9.99), often calling it an unbelievable bargain relative to espoir's normal higher price point.
Bundled brush add-on
Many buyers were motivated by getting a brush included for free or cheap alongside the highlighter/cheek product, seeing it as extra value.
Curiosity about a previously wish-listed item
Several reviewers said they had been eyeing the product for a while and finally purchased once it went on sale.
Repurchase/stockpiling
A number of loyal customers repurchased the same shade for backup stock or bought multiple color variants (pink, purple, orange) after liking one.
Influencer/idol makeup artist recommendation
At least one reviewer cited seeing a favorite idol's makeup artist use the product as the reason for purchase.