Exposure to Bitcoin-Specific Scams and Fraud.
Not just bitcoin, fiat currency sometimes used for scam and fraud.
Black Market Activity May Damage Reputation and Usefulness.
Yes you are right, but bitcoin it's wrong when they blame the tools instead the one who use it.
Susceptible to High Price Volatility.
This is why bitcoin popular for investment. I don't think this is considered as disadvantage from bitcoin.
No Chargebacks or Refunds.
Bitcoins need income too, not just user.
Potential to Be Replaced by Superior Cryptocurrency.
Yes everything is possibility, but maybe bitcoin technology it self will become better too.
Bitcoins Are Not Widely Accepted.
Of course, bitcoin life still young compared to fiat currency, it's just matter time when they realize crypto currency better than fiat currency.
Wallets Can Be Lost.
LOL every wallet can be lost, not just bitcoin even the real one.
Risk of Unknown Technical Flaws
Yeah irresponsible parties just make things worsen.
No Physical Form
This is why it's called virtual currency.