while they play a relatively small role, at least for now, bankers nonetheless view their rise as potentially dangerous to the health of the economy. Because virtual currencies aren't backed by a central bank or controlled by a central administrator, their values are vulnerable to wild swings.
Can there really be bankers out there that are worried about something with a $1B market cap? If bitcoin was a stock on NASDAQ, it'd be ranked 2100th. About the same market cap as WD-40. I don't see many bankers talking about the potential dangers of WD-40 going under. Now being on par with WD-40 is pretty impressive IMO, I still doubt most bankers have bitcoin even on their radar.
Maybe when we reach the top 500, which requires a $10B+ market cap & $900/BTC, bankers can start becoming worried of how to transition to using bitcoin instead of fiat.