Being prepared often means having the right tools. A prepper should be mentally/physically prepared and also have the mindset to ensure they're carrying essentials in the event of an emergency, or if a task arises that would require a specific tool.
A knife is one of the most basic self defense tools one can Everyday Carry (EDC). It's also a useful daily tools for basic and urgent tasks.
When selecting a bladed weapon do so with Class; Capability, Legality Access, Size, Speed. (CLASS)