For ordinary users, the biggest advantage of a credit card is that it can be overdrafted and spent in advance.

The disadvantage is that such purchases may affect your credit limit if payment (checkout) is not made on time.

As for unreasonable deductions, it seems that they have not appeared much yet. It is true that the annual fee is a bit high, but now many banks can waive the annual fee by swiping the card or making purchases.