I was making this suggestion to some folks yesterday, but they claimed that bitcoin is too small. Does it matter?
I would compare bitcoin with a $7 stock that has a market capital of 800.000.000 U$S...
It's going up, but any big shot with, say, 100-500k can manipulate the stock considerably and pump it and dump it.
As the market capitalization of bitcoin grows, the currency will be resistant of those kinds of "attacks" and hopefully, the price, although it will continue to move up perpetually, it will slowdown considerably compared to today's volatility.
Anyway, a quicker answer to your questions is NO, it's not even close to being the strongest currency in the world.
But a $7 stock isnt a currency, really, is it. I mean you need a certain amount of liquidity to be considered true currency, you could argue that bitcoin has that now. But a stock?