For example, you can control many fans at once, since everything is done in hardware. Also, it doesn't use any CPU cycles, so the PSoC core is free for other stuff (it doesn't even need to do the PID loop in software). You can try to get 52 independent PWM outputs with another MCU - when you are lucky you get 3.
You can look at the three eposiodes of PSoC Today, which shows off the fan controller component:
Generally speaking kits are for end product development, so reason you
would use PSOC is its cost-integration benefit, the ability to process analog
as well as digital signals w/o external components most of the time. The kit
helps you develop code quickly, and then you layout your own PCB using
the low cost PSOC on it.
If you are only making one fan controller than a kit makes sense, you do not
have to make PCB, plenty of example projects to get you up and running quickly.