Portability/travel convenience
Many reviewers explicitly bought the mini/keyring format for travel, small bags, or pouches, valuing that it takes up little space and doesn't waste product if mascara isn't used daily.
Repurchase of a favorite formula
A large share of reviewers already used and loved the original full-size Curl Fix Mascara and purchased the mini as a smaller/travel version or to try before committing to full size.
Cute keyring/novelty design
Multiple reviewers cited the adorable keychain design and gacha-like tiny bottle as a purchase driver, sometimes as an accessory rather than purely functional item.
Trial size before committing
Some buyers used the mini as a low-cost way to test a new shade or the brand's mascara formula before buying the regular size.
Freshness/hygiene concern with full-size product
Several reviewers noted mascara degrades or gets clumpy after opening, so they prefer buying smaller mini sizes to use it up before it goes bad.