Sure, you won't get back the same USD, but you will always get back the same amount of the underlying assets as you put it. This is the the same situation you w

Sure, you won't get back the same USD, but you will always get back the same amount of the underlying assets as you put it. This is the the same situation you would be in if you had a bank account denominated in euros. Alternatively, you can look at this like an exchange traded fund. In both cases what you are buying are tokens which represent shares of other assets.