If you have a credit card then you do not need decentralisation, same with controlling your funds because the credit card company is actually lending you money. You can generally use a credit card anywhere in the world. If you pay in bitcoin then you will need to trust the merchant you are buying from as you cannot reverse the transaction.
The main selling point that bitcoin has above credit cards is the cost of accepting/processing credit cards. Since the cost is lower when paying in bitcoin, merchants are likely to pass along these savings to the consumer.
I don't think you understand the importance of BTC being decentralised and trust less. Long story short, if you trust banks/credit card companies/financial institutions more than you trust yourself, then yes, the main benefit for you would be low tx fees.
If you use a credit card to make a purchase the bank is trusting you with their money, not the other way around. You don't need to trust the bank in any way by paying via a credit card as you have the ability to make your payment in cash, and if they say you owe more then you really do then you can not pay the bill.