An article written by Sean Cross, published in opensource describes various benefits of using open source debugger with your hardware.
Working directly with hardware is hard. Each project brings with it mundane questions of which compiler to use, what communications protocols to work with, and how to load code. Developers also need to figure out how to debug the live system without affecting the program being executed.In the past this has required expensive and proprietary software, but thanks to commodity hardware and projects such as OpenOCD, developing programs that run directly on embedded hardware is easier than ever before.