Tired of soldering each breakout board to a prototyping board? I know I am. Hence, this time saving PCB integrates the two into a single board. This greatly reduces the total amount of grunt soldering required to build a project.
I would have made the unified PCB even larger, with many more pads to support making whatever is needed on a single board, but I'm up against the 300 pin limit allowed by the PCB design software.