Here are a few reasons why you should focus on the 'business' side of the business transaction:
When the application is the business, competitive advantage means having a better application
Dynamic changes to an application's features and functions directly impact the business transaction and the overall user experience. At the end of the day, what you care about most is how your users are being serviced.
When the application is the business, managing an application is no longer just about monitoring CPU, JVM memory or timing key methods
It's really about understanding the user experience, managing the business operations and creating service levels to ensure optimum performance. Business transactions are the binding factor for attaching SLAs to business operations and for creating a common ground between dev teams and ops teams. Focusing on the business transaction is a great way to validate the whole cycle including a rollout or the current state of the app at any given time.
When the application is the business, the responsibility of managing applications (and hence the revenue stream) falls on IT Operations
But development is responsible for building the app and for the innovation in it. The creates an interdependence. By creating a common language to categorize user requests – "Are the checkouts doing ok?" "Is the sales order processing running faster than before?" – these teams are better able to communicate and effectively manage application performance over time.