In every other case, you are better off using your resources on something with a more reliable return on resource investment.
Now weighing your comment against really long odds like the lottery, its definitely more correct.
The point I wanted to make is that its fine to hope in things that are seemingly unattainable, and to be somewhat ignorant of the realities. Imagine, for example, how bad college basketball would become if players started realizing just how long the odds are in the path to wealth through the NBA.
It turns out, a lot of our economy runs on hope.
Just because you are gambling with your life doesn't mean you can't gamble better. Problem is when people get delusional about what they can achieve vs. the reality. Most people are born and remain losers. My motto in life is to preserve my capital, so I can lose for as long as possible.
I am trying to weakly correlate this concept to startups. You have to start out dreamy-eyed enough to start. You can deal with reality later.
When Scott Mace and I started CalendarHub and applied to YCombinator in the same year as Justin Khans Kiko, we weren't shooting for lifestyle business. We were shooting for Get-Bought-By-Google or bust. Reality set in later. That was my start, at least I started :).
Playing my own devil's advocate: C3P0 states the odds for successfully navigating an asteroid belt, but Han doesn't want the odds, mainly because C3P0 hasn't stated the odds for Han Solo succesfully navigating an asteroid belt. Han works best when he doesn't know how often other people fail.