What I like about it (I use it) is that it lets me drive code in low-level, somewhat math-incapable languages at compile time. I have a project right now that

What I like about it (I use it) is that it lets me drive code in low-level, somewhat math-incapable languages at compile time. I have a project right now that does real-time signal processing in an FPGA. The actual project itself is organized in Verilog, which is cumbersome to do math raw math in. I use cog in my build to do a bunch of preprocessing math in python. For example, since I use cog to calculate a bunch of constants (for coefficients and the like), I can change the sample rate in one control file and the compilation process will re-do all the math for me.