Is hope just a tool to help us deal with reality or does it actually help forge a new reality?
As @CapriKious said below, it becomes dangerous as a substitute for constructive action, and I'd add, still a stronger contributor to success than despair.
Despair or Hope, That would be a binary analysis of possible ways of responding to a situation. Both could just as well lead to action or inaction. I could not say that one is superior to the other. One would obviously be more pleasant than the other, but one would be hard pressed to show that there are no alternatives to having one emotional response or another. I would say that reason would be more useful than any set of binary emotional alternatives. Emotional satisfaction being as poor a master as dissatisfaction. Only contributor to any success I would say is, Appropriate action or inaction in service to the wanted goal not the emotional response that preceded it.
Live long and prosper.
I think hope is a double edged sword in our set of coping mechanisms. It is what we do when we have no idea what else to do. When we cannot see our way out of a situation hope can keep us going until better circumstances come along. Contrarily, It can keep us at a course of action that is in fact quite useless. It is irrational as are all the emotions and has the same advantages and liabilities. I think rest and reflection or useful action is a better response than hope as it (hope) can be a substitute for positive actions cerebral and physical.