1
It ensures that a business remains a going concern in the event of death or incapacitation of the "key person" that might otherwise jeopardize the continuation of operations.
2
It helps map out a smooth transition for successor co-owners/shareholders in the event of death, permanent incapacitation, and retirement.
3
It's an important tool in ensuring financial liquidity, pre-empting major problems that may arise in the event of death of one of the owners.