Business solutions can be described from different views. Architecturally these views can be generated as conceptual, logical and physical. Each of these layers considers business in different terms. These views can and should be considered holistically to gain a fuller understanding of the business.
Another way we can generate views of the business is to compose the views based on the domains of thought people in the enterprise use as they perform their responsibilities (e.g., the legal department, marketing, C-level management).
Discussion of the differences between these domains as they extend across the different layers can be valuable because it presents a more complete view and allows for evaluating domain specific values against more widely held business values or requirements..
Architecture brings to the business a framework for making these discussions less personal, subjective and chaotic. Architecture provides a rigor to the communication by evaluating current state of the business, defining desired future state and consistently articulating business plans for moving from current to future state.
From the framework architecture provides senior management can determine budgets, implement programs, communicate consistently to internal and external partners and customers and evaluate the effectiveness of business predictions against actual implementations.
Without architecture the business would tend to devolve into fiefdoms of systems owners who decide their next steps based on the value to their specific area of the business at the time of the decision. Corporate politics in a large business can foster a dysfunction of areas pitted against one another without firm leadership or the vision that architecture can enable.
With thanks to my mentor, @scmunk.