uh oh i said the ultimate question. Now you answer
There is a need for anonymity with everyday transactions. For example, the Target data breach shows that people not doing anything illegal were victimized by being transparent in their financial matters. If all those Target credit card transactions had been in bitcoin rather than credit card, there would be no need for victims to change their credit card numbers and pay for identity theft protection.
I may go to a shady pawn shop and buy a used computer. Normally I'd pay cash, but I'd never dream of using a credit card, so that the meth heads in the back can later charge some porn on that card. I'd have no problem in paying in bitcoin.
People use credit cause they want to buy now pay later. Thats what credit is. They could have just used cash at Target and no identity theft either.