Very aptly put, the versatility of Bitcoin is one of the factors that gives it value as it appeals to several classes of people. This coupled with its other advantages may actually limit its use in the long term as a means of making daily payments. Why spend my $100 worth of bitcoin on a bicycle when those bitcoins could be worth $121 by the next day? People still ask if the 10,000BTC for 2 pizzas guy still regrets it, well spending 0.002BTC for 2 pizzas would likely be ridiculous a decade from now.
Merchants may eventually switch from payment processors when they recognize this huge value potential as you said, but would more people be willing to give away bitcoins.