Process automation for small medium sized business is an opportunity to align the process with the business’s strategy, eliminate waste and take control of a business asset (how you deliver your service or product).
The engine ensures that every customer gets exactly the same experience, additional controls can highlight when SLAs are broken and the engine can deliver a lot of reporting information about each process.
When changes to the business logic need to be made, then the BPMN diagram is changed and then re-deployed onto the process engine (a relatively quick process).