Low self-esteem is a symptom, and (repeating a bunch of others with this statement) not the cause.
AS is predominantly a social dysfunction - we don't relate to others the way they expect us to. This leads, when we are young, to bullying and exclusion. When we are older, it results in scapegoating and political indictment, oh, and exclusion again.
Which leads to low self-esteem.
Therapy, and more specifically CBT, can certainly help lessen the impact of self-esteem issues. Anything that helps you function more effectively in the NT world is going to make you feel better, and I think that is worthwhile. But there is no "cure" for AS. If you were to suddenly discover that your problems were entirely related to low self-esteem, then I would posit that AS was never a factor to begin with (I will acknowledge that extremely low self-esteem might appear at a glance to be AS-like).
Personally, my self-esteem fluctuates wildly - if I solve a particularly heinous problem at work I'm "king of the world", but if I mess up a social situation I'm "king of the stinking-pile-of-feces-that-is-my-life".
Bottom line - if it makes you feel better then there's nothing wrong with it (though be leery of any solution that costs $$$). But if you're AS and you think it's gonna "cure" you then you're just riding the positive-feeling wave. At the end of the day you're still gonna be you, and no amount of Tony Robbins "I am special" stuff is going to change that in the long term.
Nick