The biggest problem is that right now the financial infrastructure that exists to handle transactions for other things doesn't quite exist for bitcoin. If you send your money to a bitcoin exchange, how do you know that people won't run away with it?
That's why people use escrow for secure your fund especially when bitcoin identical with scam
Since bitcoin is limited in 21 million coins, I fear nothing , the problem only will be bitcoin survive until 2020 or not !?