Obviously putting some % of your savings into it can be rational, but putting 100% of your savings in a volatile security just isn't wise.

>That's a dumb move indeed, unless you win of course.

No, betting everything you own on red when playing roulette is still a dumb move even if you win. Sometimes you can still be lucky while being dumb, but that's it. Similarly, it's dumb to wrestle a grizzly bear on a bet, even if you come out alive and win the bet.