Title needs to be amended: Bitcoin could be worth 100x more than today...if you trust the Winklevii.
That's a pretty big "gotcha".
Since it has demonstrably gone up 10× every year and even conservative people think $35,000 per bitcoin is doable, there's really not that much of a gotcha. (The highest reasonable estimates are around $300,000 per bitcoin, which would mean it could be worth 1000× what it is today.)