I'm a tad confused (easy I know )

I read this as using an RC transmitter sending signals to a receiver, you then connect the first five channels from the RX via diodes to a single pin on the PIC which then drives 4 servos driven from the PIC as it's decoded each channel ...

What's the use of the PIC, why not simply connect 4 servos direct to the RC receiver and get the same result ?