one of the biggest problem with dollar is inflation.. over time all currencies lose purchasing power because government keep printing more money.. with bitcoin you don't have this problem because the system is designed to make bitcoins to be finite.. only about 21 million bitcoins will ever be released.. the release of new bitcoins is slowly down and it will stop completely within few decades..
No matter how much value fiat currencies are losing after years, people will continue to use it without thinking about the consequences.
These people are like sheeps. They do what their other fellow human being is doing.
bitcoin is not money, while the dollar is money.
Both have a different role and if I may say both have their world, respectively.
bitcoin might be used more as an investment like gold but also at the same time bitcoin can and is being used as a currency (money) too.
maybe your definition of money is off, but as long as you can pay for stuff with bitcoin, it can be considered as money.