A platinum credit card is still a credit card. It is just a fancy name to make exciting what would otherwise be boring. For a person who holds one, a platinum card is a marker of financial success or at least of spending prudence.
These special cards do have some genuine advantages, such as a higher maximum and lower annual interest. It is awarded to consumers with above average credit ratings and who also have the purchasing power to safely take things out on credit.
As glamorous as the name sounds, platinum credit cards are actually very common, especially for individuals over 30. To qualify, a person simply needs to have a good credit rating and a history of credit card use that has not soured. It also helps if the person has a good job. A person working a tenuous job at a fast food restaurant would likely be turned down for a platinum card, and probably should not be using one.
On the other hand, the reduced interest rate could be extremely handy to anyone wanting to switch from a card already loaded with debt.
A credit card is intended to be a short term line of credit, used to meet unexpected expenses. The interest rate on a credit card is high because of the risks associated with open-ended borrowing. Credit cards are used to make spontaneous choices, but a person who does not pay them off quickly will be forced to pay a great deal of money in interest, even with a premium card.
A platinum credit card does offer some choice perks, such as no annual fee. Some cards have built-in insurance for purchased items. A platinum card is in some ways like carrying around a bank loan in your wallet, to be used on an instant.
Real loans might have a lower instant, but one does not have to go through the hassle of applying for it. Credit cards are about convenience.