You seem earnest, so I am going to try not to be frustrated, but depression is not a gift that results in creative genius. People who manage to struggle through it and create art are doing it despite their disease and not because of it. The romanticism that is attached to the suffering artist is incredibly frustrating and, I think, dangerous. It leads people to believe that it is okay or worthwhile or noble to let this illness rule over you. We don't celebrate cancer or dementia or schizophrenia as "gifts". Sometimes people suffering from those illnesses are able to create beautiful works, but we don't romanticize their diseases because of it. Why would/should we do that with depression?
I agree with you, but just as a counterpoint, Dostoevsky valued his seizures because of the insight filled "halo" state that he would enter into before they came.
