I think it depends what is your goal. If you want to buy cryptos with money borrowed from the bank just to fund your purchases with crypto , it is highly not advisable. It's best to use cash that you would have in the bank.
There is the problem of using cash earnings from cryptos to pay the credit card. There is a risk of fighting and racing against time to pay for the credit card interest and principle which usually adds up over time. I made this mistake many many years ago when I was investing in stocks and making some amount of money. One day, I was given this credit card by the bank due to my loan approval from a bank. So one day, while I was investing, I was thinking, why not just cash out the cash from the credit card to fund the investment and to see if i could make money quickly then i could pay off the credit card. I was dead wrong. I made some huge losses and had to bear with the lost and pain for many years and did not even invest for an amount of time.
I think it's better to gather up some funds and earn slowly. Built a solid foundation brick by brick so it won't easily topple when any winds come or armies of zombies come to attack our castle. Better built wealth slow and steady. Credit card is easy cash and the lost will be amplified if lose our cash in cryptos. At the moment, it is not shown whether there is a 100 percent that BTC and other cryptos may go uptrend.