There's an important distinction that you seem to be missing: the brain appears to be designed in such a way that we are able to think and decide on best courses of actions but find ourselves not actually implementing them.

I'm not missing that distinction; what you're missing is that this is an indication that the conscious "decision" being made is based on incomplete information about one's preferences.

That is, if you experience akrasia, this is an indication that your conscious reasoning is flawed. (Your "unconscious" reasoning may also be flawed or based on cached thoughts, but this does not exempt your conscious reasoning from its failure to take into account your actual preferences.)

Thus, saying we should "fight akrasia" is like saying that we should fight the "low fuel" warning light on our car, when what's actually needed is to put gas in! The warning light is doing you a favor, so calling it bad names isn't helping.