Well to balance daylight you are not using blue or green correction gels on strobes. But they do have lots of good uses, creating or adding mood or ambiance, though I find the bolder gels more applicable most of the time, you have to print big to get the subtler shades of gel to come out effectively within a scene, IMHO.
Traditionally green correction gels are used to make flash the same colour as some fluorescent lights and blue is used to make tungsten lamps daylight balanced, obviously neither is relevant to flash to daylight correction.
First shot below is a shot with three flashes with different gels, (plus four tungsten lamps, a TV and the car tail lamps) one red, to exaggerate the tail lamps outside, one with both blue and purple to mimic the TV output, and one CTO to match the tungsten lamp light. But it is totally irrelevant to the subject of daylight balancing strobes.
Mid day strobes are pretty close to daylight and need no correction, early and late in the day 1/4, 1/2 and full CTO and CTS are all very useful.
Second shot is a late afternoon strobe to daylight balanced shot. 1/2 CTO on the strobe into an umbrella to match the setting sun.
