Multi-use versatility
Many buyers purchased it not just for eyeliner but for aegyosal (under-eye line), triangle-zone shading, brows, and blending gel/cream liners, appreciating one brush covering multiple steps.
Affordability vs. quality
Reviewers repeatedly note it performs as well as or better than pricier Western or drugstore brushes while being very cheap, driving purchase and repurchase decisions.
Brand trust / repeat brand purchase
Many customers already own other Fillimilli brushes and buy this one because they trust the brand's consistent quality ('fili brushes are always good').
Pairing with specific liner products
Several reviewers bought it specifically to use with Holika Holika gel liners, romand gel liner, or Hince Jelly Liner, suggesting cross-brand bundling potential.
Replacement/repurchase after wear
Some buyers repurchased after their previous brush became frayed or lost its sharp point, indicating recurring replacement demand.