what I just said before (about scammers). Bitcoins is unsafe for customers, because transactions are irreversible.
Cash payments also are irreversible.
because it is not convenient to use.
Blockchain.info online wallet is as easy to use as online banking systems.
because the fees are too high
and confirmations too slow.
You can accept micro-transactions without waiting any confirmations, it is not just worth for scammer to perform an attack.
Off-blockchain services like Inputs.io offer zero fee transfers.
P.S. I think next major adopter of Bitcoin will be porn industry because elimination of the chargebacks is great advantage for these companies.