Out of the emotions, the feeling urging us to avoid negative consequences seems pretty useful haha
You say fear is good, presumably because it stops you from doing things you don't know are dangerous.
But then you say you can do a technique to defeat fear when you know the fear is irrational.
But your argument starts from the premise that you don't know a situation is dangerous or not without the fear so how would you know it's irrational?
In my experience it's the opposite, most fear is not useful.