Let me rephrase the questions
Example 1: What if a person was cash poor and so used a credit card to buy 1 bitcoin ($3577USD). Then bitcoin goes on a downward trend for the next 1 year down to $577.
Now the person is not just $3000 in the hole but the interest rates start coming.... how is that going to pan out for them???
Example 2: A person was cash poor and used a credit card to buy 1 bitcoin ($3577). Then they used a second credit card to buy another 1 bitcoin. And then a third card to buy yet another 1 bitcoin. The three cards they used are 0% interest for 18 months. After 3 months after buying the 3 bitcoins, price increases. Bitcoin goes up two thousand dollars to $5577. With 3 bitcoins, they now have $6,000 profit. So they cash out.
You could have added this in your opening thread so that the people who replied above really never understood what you meant or either they did not read properly and just started replying. Example 1: What if a person was cash poor and so used a credit card to buy 1 bitcoin ($3577USD). Then bitcoin goes on a downward trend for the next 1 year down to $577.
Now the person is not just $3000 in the hole but the interest rates start coming.... how is that going to pan out for them???
Example 2: A person was cash poor and used a credit card to buy 1 bitcoin ($3577). Then they used a second credit card to buy another 1 bitcoin. And then a third card to buy yet another 1 bitcoin. The three cards they used are 0% interest for 18 months. After 3 months after buying the 3 bitcoins, price increases. Bitcoin goes up two thousand dollars to $5577. With 3 bitcoins, they now have $6,000 profit. So they cash out.
My suggestion is to never use credit to purchase bitcoin as it will end up putting you in a hole without a doubt and i personally know some friends who did purchase when the market was rallying and when the crash happened they had to minimize the loss by lessing at an amount feasible. If the market is on a rally then there is not an issue, if not never ever try. 
