The main purpose for most businesses is to create a positive net result. This will enable the business not only to survive in the long run but also to grow and develop.
The property insurance covers the interest of the property itself. The business interruption insurance will protect the net result of the insured by compensating the financial loss after a loss. A bit simplified you can say that the property insurance protects the balance sheet and the business interruption insurance protects the profit and loss statement.