I don't think they would need to occur that frequently for it to be useful for disability insurers to be able recommend CBT and GET. The individual liability for an insurer would very often be 100 times that and sometimes several hundred times that.
As Valentijn says, a percentage of people give up if they get turned down for disability payments. I have seen this both with public and private disability payments.
Also then in other cases where people do appeal, if the insurer can say that they offered therapy that has evidence for it, patients can lose out if they have not built up a strong case. I can recall one person who went to regulator without having built up a strong case to rebut it (being turned down).
So I could easily see how it could be financially worthwhile for insurance companies to offer to pay for such therapies.
It also doesn't help if you have an idiot for a lawyer, I can attest to that from personal experience. Different country though.