Craig shows you how to have reverb/tone via the FX150 speaker, but send a dry signal to the FOH. This can be really handy when your engineer wants control over your FOH effects, but you want control over your sound via the FX150.
This setup works with an incoming monitor mix via CH1, since you don't use the OUT connection, just the THRU.
One caveat of this approach is that you lose the ability to "daisy chain" several FX150's together, sharing a monitor mix.
