The fact of the matter is that bitcoins are currently the best available solution to a very difficult problem. That problem being how to instantly and (mostly) anonymously send money irreversibly for a very low fee. They are also, in some instances, the only possible payment for goods and services (which is the exact definition of money). As such, they have value and will continue to have value until such a time as a better solution to that problem is developed.
Whether their current value relative to USD or another currency will increase or decrease in the future is irrelevant to the point of whether bitcoins have value (they do) and are used as money (they are).
Whether their current value relative to USD or another currency will increase or decrease in the future is irrelevant to the point of whether bitcoins have value (they do) and are used as money (they are).
