I pay for CMOS Online. Why do I have to pay for PerfectIt to access The Chicago Manual of Style for PerfectIt?

The Chicago Manual of Style for PerfectIt is a joint product produced by the University of Chicago Press (the authors of The Chicago Manual of Style) and Intelligent Editing (the developers of PerfectIt). The Chicago Manual of Style for PerfectIt is a supplement to the Manual that requires a subscription to PerfectIt as well as CMOS Online.