A business process allows a business analyst to understand who is involved and what they do in order to fulfill a business process.
An ecosystem map allows a business analyst to understand who is involved and what is exchanged within the context of a business.
Both of these diagrams are looking at the same thing from different perspectives.
The business process allows a business analyst to see bottlenecks and inefficiencies in the process.
The ecosystem map allows the business analyst to see what is being exchanged between stakeholders which may lead to new understandings of the roles being played which will then result in more effective processes.
The more ways we can look at a problem the better the resulting solution.