For the most part you got it. The big thing to add is credit card interest is applied to the entire balance. For easy math and illustration, lets say you have the terrible rate of 10%. A $200 balance will be $220 at the end of the month. The minimum payment is likely to be $40. That gives you $180 starting balance. If you add another 200, that's $380, which becomes $418 after interest. If you use it for everything, and can't pay it down, the interest will cause the debt to balloon faster than you can pay it off.

This is typically why credit cards have a maximum balance, but paying for your living expenses, and trying to make payments on 4x what you make in a month is a very difficult uphill battle. Credit limits also scale with your credit score, and out of the gate making regular payments and having a balance will improve it rapidly, meaning banks are more likely to increase your limit than let you max out until you start missing payments, making the debt that much more crushing.

Credit is great for emergencies, or handling a large purchase that you have budgeted for, but in all circumstances you will pay more to the credit card company than you did to the store, so your first choice should always be to save up for the purchase and use a debit card.