That 'small percent' of online vendors is growing about the same percentage rate as Google and Facebook when they first started. Your incredulous attitude will only prevent you from getting into Bitcoin and realizing the benefits before it becomes ubiquitous.
Bitcoin started as an experiment.. Now you can buy anything on Overstock, Tiger Direct, Newegg, Cheapair.com, and Expedia with Bitcoin. You can also pay your Dish Network bill with Bitcoin. There is an organic infrastructure growing around Bitcoin - US government regulations, payment innovations, website integrations - and that infrastructure is increasing momentum.
Of course it's not ubiquitous yet.. But god damn, your questions are meant to criticize Bitcoin - but they are awfully dimwitted. First, maybe 10 years ago it was seen as limiting market exposure if users needed to own a smartphone. But, there isn't a company left that worries about being out of the huge capital markets of 'users without smartphones' except maybe Walmart.
And, 'how will you buy gas and food with that?' .. Good question there. Wow.. You found one huge flaw in Bitcoin. It's impossible to buy gas or food with Bitcoin.