Cheaper – don’t buy a new knife, you can have a fully usable knife without the expense of a new knife.
Efficiency – a knife without chips or nicks is better at cutting smoothly.
Safer- nicks and chips can cause blade to get hung up, making you use more force to cut, potentially causing injury.
Sentimental-you can continue to use your grandma’s kitchen knives or your father’s old hunting knives for many more years.