Blades are not reliable weapons against zombies. While able to cut through skulls and necks, they're not good at it. They are only good as long as they're sharp, are liable to get stuck in bone, and require considerable skill to effectively wield. Daggers especially do not have the leverage to be able to function as makeshit blunt weapons, and have extremely poor range that makes it impossible to engage a zombie outside of its own range. The best melee weapon for a zombie apocalypse is a two-handed warhammer or warmace with a spike on the end, between 1 and 1.2 metres long.
