Why information systems are so important for business today?

Information systems are a foundation for conducting business today.A good Information System will only reap the benefits if the companies gain insight to better align strategies and identify critical relationships and gaps along company dimensions of people, processes, culture, and infrastructure. A good Information System provides a framework for companies to evaluate themselves relative to dimensions. By understanding and improving alignment with these critical dimensions, companies can maximize the value and impact of information as a strategic corporate asset to gain competitive advantage. 

It helps management to manage business in the current competitive business environment efficiently.

In my opinion,information has always been playing critical role in business all along from day one, the barter stage. However, with increase in complexity of business process, the need for obtaining and provisioning of  appropriate information and at appropriate time became significant. That's how data evolved into information and then to Information System. Moreover, I do not confine my comment to computerized/automated information system. This is equally applicable for all types of Information Systems.

In generic terms, all systems including business ones have certain inputs, processes and outputs. None of these components can have existence without relevant information content.