The Scrum Master role was created to address challenges that Agile Teams had when working in Products and Projects where the urgent always overcame the important. Traditionally Teams are on a relentless drive to deliver the next Feature resulting in an inability to improve the way they work. Further Teams often have to respond to the current crisis-de-jour resulting in an inability to meet planned commitments. The Scrum Master role is thus:
Sheep dog: Protecting the Team from outside interference,
Coach: Coaching the Team to improve, and
Facilitator: To assist the Team in making decisions, etc.
Without a Scrum Master organizations often have a number of problems:
Teams do not become effective at working together
Teams do not take the time to improve their work practice
Teams do not understand what kinds of opportunities are “out there” to improve
Interruptions to the work happens as stakeholders (managers, support, etc.) go directly to Team members to get their issue addressed
Teams do not appear to meet commitments they have made, as the interruptions and lack of priority result in churn