My main question still remained unanswered:
If there is no guarantee that the bitcoin's price is gonna go up and allow the average Joe to profit from it, why should he buy bitcoin to use it as a currency?
Average Joe should use it for all of his online purchases through Amazon, Best Buy, Target, any retailer who sells gift cards through gyft.com. Why?
Because Joe gets
3% discount for using bitcoin, that's why. And Joe can insulate himself completely from bitcoin price fluctuations by converting USD->BTC at the time of purchase at a place like coinbase.