System design knowledge is crucial for an SDE-2 role because: - Role Expectations: As a senior engineer, you're expected to design systems that are efficient, scalable, and maintainable. - Real-World Applications: You'll often work on complex projects that require a deep understanding of how different components interact in a distributed environment. - Interview Focus: Microsoft interviews emphasise your ability to design systems, discuss trade-offs, and adapt designs for future needs or scalability concerns.