Novelty of plumping + lip pencil format
Many reviewers say they bought it specifically because a plumping effect in a pencil/liner format is rare and 'innovative' (プランパー効果のあるリップペンシルは珍しい), which drove first-time trial purchases.
Word-of-mouth and review curiosity
Several buyers explicitly say they purchased after reading many positive reviews or hearing about it from others (口コミが気になって購入, 'heard a lot of good reviews').
Repeat purchase / shade collecting
A large share of reviews are repurchases or additional-shade purchases, with buyers noting this is their 2nd, 3rd, or 4th tube and wanting to collect the full color range.
Brand trust and price/value
Reviewers cite peripera as an affordable, reliably good-value brand that frequently releases unique products, encouraging low-risk trial buying.
Cute packaging and gimmick appeal
The heart-shaped clip, pen-like design, and built-in silicone smudger tip were mentioned as reasons for purchase, especially among younger/social-media-influenced buyers.