Do I even need credit cards?
Should I start using a credit card or it's something like a loan, which is generally bad and you shouldn't make it if possible. Please advise.
It depends on your interest rate, and your financial responsibility as a person.
If you get a new credit card and it has a 0% intro APR (annual percentage rate) for the first year or so, all you have to do is pay the minimum payments per month.
So if you need to make a big purchase, say a new TV or computer, you could put it on the card and just pay the minimum monthly payments each month. In effect getting a 0% loan for a year or so.
However, in order to take advantage of this situation you must be able to pay back the whole amount before your 0% APR is up.
The banks do this because they have millions of customers, and many of them pay interest, do balance transfers, take out cash lines of credit, etc... This is how they make money for themselves.
In response to your other question, if you were to die, the debt would go to your estate. Probably your surviving next of kin.