Well, if you don't mind me answering a question with a questions, more effective at what? If it just makes you more effective at getting what you want, whether or not what you want is the right thing to want, then it's only helpful to the extent that you want the right things, and harmful to the extent that you want the wrong things. That's nothing very great, and certainly nothing to spend a lot of time improving.

But if rationality can make you want, and make you more effective at getting, good things only, then it's an inestimable treasure, and worth a lifetime's pursuit. The 'morally good' seems to me the right word for what is in every possible case good, and never bad.