@ Peter R

That analysis has so many flaws

(1) You assume that Bob has only 2 choices (BTC yes or no) when he could diversify his portfolio in many asset classes

(2) Standard deviation is determined by using historical data not random numbers projected into the future

(3) Probability isn't randomly calculated like that.  5% lose all money vs 95% not lose all money?  Say what?  

(4) I think someone else defined "store of value" = low volatility.   I'm not sure how you are defining "store of value".  Sounds like you are saying BTC is a store of value because it could go to x20 or not.  This sounds like a "speculative" bet not a "store of value" bet.  You are speculating that demise of USD will drive up BTC price.  

(5) Buying BTC is not a hedge against USD.  That's not how hedges work.  A hedge is when you take trade AND you also take the opposite of that trade to mitigate your risk.  The easiest way to hedge is using options.  But there is no options market on BTC so the point is moot

"but I have never found a rational case where it is not wise to store at least a small portion of your wealth in bit coin"  

How about in the case the price crashes and you lose your money?  If you have the assumption BTC will forever go up in price then by all means invest.  But don't claim that the price can't crash or even go to zero.