It's probably because once you lose it to thieves, it's gone. Then again, so is Bitcoin and it will take awhile for credit cards to be replaced. I guess for me, I prefer to use the card because of the perks like airmiles.
Not true! I hate using card! I got in so much debt before because I would use my card and I lost track of my spendings. I only use cash now.
If you cannot really track or you are not disciplined enough to pay on time with your credit card, then you should really pay cash all the time. But there are people who opt to use cards and btc because it is more convenient for them.