A startup plans to launch a web application without buying physical servers. Which cloud benefit does this illustrate?

This scenario illustrates the benefit of operational expenditure (OpEx). By using cloud services, the startup pays for resources as they consume them, similar to a utility bill. This avoids the large upfront investment in physical hardware, which would be a capital expenditure (CapEx). While cloud computing also offers high availability and scalability, the core benefit highlighted by "without buying physical servers" directly relates to the shift from CapEx to OpEx. The question focuses on the financial model of acquiring resources, not the technical capabilities once acquired.