I agree about depression. Depression (and many other psychological problems that are treated by CBT, like anxiety, drug addictions or interpersonal relationship problems) is heavily related to akrasia. If we accept cognitive model of CBT, its basic premise that depression is caused by irrational thinking (at least in significant part of depressed people and/or at least to a significant extent), then fighting depression becomes similar to improving your epistemic rationality. Obviously, overcoming depression is crucial for instrumental rationality too, because depressed people are extremely unhappy and counter-productive.

What I really liked about Yudkowsky after reading The Craft and the Community sequence is that he admitted many times that the art of rationality is only a small part of what it's supposed to be, that even though we know much about punching now (how to think clearly about epistemological issues), we barely know anything about kicking (how to overcome akrasia), let alone grappling, wrestling, painful holds (whatever that corresponds to).

Overcoming procrastination, chronic sadness, low self-esteem, drug addictions, insecurities, bad relationships, anxiety and panic attacks, envy, jealousy, bigotry, compulsive disorders, personality disorders and any other cognitive and behavioral failure mode could raise the sanity and productivity of so many people to such a huge level. Once LW knows how to treat akrasia at least as effectively as all psychotherapy and self-help movements, it will be massively helpful for millions of people.