With PSoC Creator, you're not really programming via the editor GUI. You're actually configuring the internal hardware, which is compiled into routines and tables that are run through the chip at startup. Think of it more like an FPGA where you are hooking gates and blocks up to various pins. The software can also control and redirect these lines from inside running code, but having the GUI set things up for you is a lot easier than spending a week with the Technical Reference Manual...all 1000+ pages of it.