I have always seen the Internet advise against it. Although I have made profit in this way.
Mostly many are afraid due to the credit card fraud and we dont want the same issue with us in the future. There are many such scam sites which would stole your credit card numbers abd wont give bitcoins in returns. We should keep away from such sites.
Also credit card purchasing takes a lot time for the confirmations and we get the amount of bitcoins after a huge time. In that time the price for bitcoins can go down or can go up and could prove to not be profitable. This is what keeps peoples away from purrchasing bitcoins with their credit cards. Instead it is good to purchase bitcoins with cash from a dealer.