It’s impossible to get a solid, well-rounded CS education without understanding computer organization and architecture because too many things depend on such understanding.
Performance analysis of practical software
Parallel software and its execution
Embedded and mobile computing
High-performance game programming
High-performance databases
Accelerators, GPGPU computing and related topics
Modern compilers and code optimization
Low- and mid-level networking issues
Computer Organization and Architecture lets you know how exactly each instruction is executed at the micro level. If you plan to study embedded systems/ processor design, these concepts are very important, as they form the basis of design strategy. It is also a well-known fact that assembly coding is closest to the computer, and it is always most optimum, if written properly.