I think it's great. I have one book on it and keep going back to it for my own use. We could all use it.
I've used it for my fear of flying... it's a lot of work, so for a little kid, it depends upon the child's maturity and skill level. For eg. the night b4 a flight, I'd lie in bed, panicking, and not sleep a wink. Using cognitive therapy, I'd have to say, "I'm safe in bed, I'm not even on a plane right now, and I need to sleep." Those thoughts had to replace thoughts of everything from turbulence to crashing to terrorists. I realize that some of those thoughts are legitimate, but statistically, flying is no worse than crossing the street and risking being hit by a drunk driver.
So you repeat and repeat the "Good" thoughts. It's a lot of work (I know I already said that, but it really is work.)
It's sometimes hard to identify exactly which are the incorrect thoughts, so in the beginning, it helps to have a therapist.
If there are other people involved, it helps to have everyone practice role playing and scripting. Eg, it's typical for newlyweds to take things personally (or in the case of my mother, take everything personally!!!) and catastrophize. Eg if the husband says, "Let's go to a movie tonight," and the wife says, "Great!" she gets all dressed up, ready to go, and at the last min., husband says, "I can't find any movies I want to go to."
Wife has a fit, says "You don't love me," they get into a big fight.
Of course husband should have consulted wife waaay earlier in the day about the type of movie, and finding nothing he liked, should have said, "I'd like to spend the evening with you alone, but I'm really disappointed that there aren't any good movies out there."
The fact is that he didn't find any movies he liked... he never said he didn't like/love his wife.
It sounds really simple.
It's not. I repeat, it's hard work.
But well worth it.