Different people have different preferences. Just like how some people prefer to use cash when dealing, some prefer debit card, some credit card and etc. Each method have their advantages and disadvantages, but people still use them. Same argument for bitcoins.
Yes I agree to you different people have different preferences. For me I use to prefer debit card than credit card because Big advantage if you have a cash on your hands. If you want to buy something you have a cash on hand.