Analyzing for business. If you tend to be technology-focused, a business process model can really help you break away from the software or system-focus that you cover in a use case.
If you know more about the business than about the technology, a business process model is a tool you can use to analyze and communicate the information you have about what the business wants without getting into the technical details.
And if technology changes tend to create a lot of headache, a business process model might help you discover a lot of improvements you can make without touching the technology systems at all.