Crack climbing punishes the wrong shoe in two specific ways: low-cut shoes leave your ankles exposed to abrasion as you jam them in, and downturned shoes refuse to slot into thin cracks because the toe is curled. The right crack shoe is flat, stiff, high-cut around the ankle, and built from leather or thick synthetic that resists abrasion.
This is a small category — only a handful of shoes are designed specifically for crack and trad. Most are dual-purpose with slabs and multi-pitch routes, where the same flat-stiff-high-cut profile works.