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If you are traveling and lose your credit card, but in a country that has a reasonably active Bitcoin scene, you can sell some BTC to pay bills while "over there".
This may become an issue for us.
Here is a case for having an online wallet, "travels anywhere".
There are other ways as well, but not as convenient as online wallet. i do keep some BTC in online wallet for spending purposes. one day all the stores across the globe will be accepting bitcoin payment(i'm waiting for that day to happen).