I definitely agree with this statement and supporting opinion from Mike Cohn. I have seen this in a few cases in smaller companies where Agile Development is only beginning to take hold and where the tech team has largely been responsible for the product development. At that early growth stage Agile methods are considered a purely tech thing and there may not even be a product manager role, so when you have to talk about the Product Owner role there isn’t anyone but the Scrum Master to assign the task.
From Mike’s Blog Post:
Different individuals should fill these two roles, and there are many reasons for this. Let’s consider a few of them in this post.
Each Has a Different Focus
First, a product owner and ScrumMaster are focused on different aspects of a Scrum project. The product owner spends his or her time thinking about what to build. That should largely be determined independent of the capabilities of the team, which are the concern of the ScrumMaster.
That is, while a product owner is determining what to build, the ScrumMaster is helping the team work together so they can.
In many ways, this can be thought of as similar to the idea that a team’s programmer and tester should be separate. Sure, a good programmer can test and a good tester can program. But, separating those roles is usually a good idea.
Read the entire article – ScrumMasters Should Not Also Be Product Owners