Because Banks in Britain and the United States have banned the purchase of cryptocurrency by credit card. This is bad news makes bitcoin and cryptocurrency market are going down. 
This is a good thing. People shouldnt be able to invest in Bitcoin with credit - money they dont have, which inflates the price, creating a fake price built around debt. This is not good for the long term of Bitcoin or crypto market as a whole. I think the banning of credit cards is a good move which may drop the price initially but will help to drive the price to ATH's in the future.
I agree with you. The prohibition of credit cards to pay for bitcoin and other cryptocurrency is suitable because its price is unstable. Trader are very easy to lose money and can not afford to pay debts to the bank.
I think Bitcoin and other cryptocurrency should be long-term investment and should invest by saving money. Avoiding borrowing or pouring out assets into it will be very risky.