It may be important to this law, but that doesn't mean that it is used specially (as in, in any but its most contextually-obvious general-use sense) in the law.
I mean, the meaning of "is" is also very important to the meaning of most laws, but is rarely defined in the enactment.
> You can't classify something as digital currency without knowing what value means
True, but that doesn't take a non-standard, law-specific definition.
> or how to measure it.
Untrue -- quantification of value is not relevant to the definition.
Value is being discussed (even though you appear to be using an unrevealed definition) as a quantity (maybe, I am wrong, and it is not a quantity), which means there must be a way to quantify it.
For someone to claim that the numbers I hold represent something else, is an error.
>“Digital currency” means any digital representation of value
You can't classify something as digital currency without knowing what value means or how to measure it.