Yup, I'm familiar, I've tried it, but my brain is somehow unable to treat the small accomplished tasks as separate from the larger task.

It still costs me the same "percentage of willpower", if you will, as I would have spent tackling it as the first step of the larger task. And once the willpower runs out, it's out.

With video games it's not that different. What keeps me playing aren't the small rewards. If small rewards were enough to keep me going I'd play pacman all the time. The only thing that keeps me going is curiosity.