Take Bitcoin for example. It's a financial asset to whoever holds it. To whom is it a financial liability? I suppose you could say "it is a liability to the whole community of those who accept Bitcoin in exchange for goods". But that answer seems like a desperate attempt to salvage the assets=liabilities dogma. Nobody is obligated to accept Bitcoin.
Here's the right way to think about it. It's quite simple really. Very basic economics.
Suppose I sell you my car for $2,000. That would only happen if I value my car at less than $2,000, and you value my car at more than $2,000. So when I sell you my car, it must mean that the value of the car increases.