Asymmetric cryptography is a completely separate, much older technology that has nothing directly to do with cryptocurrencies.
Furthermore, Bitcoin does nothing to solve the kind of fraud problems you are talking about, and in fact makes the consequences of them much worse, since you no longer have a central authorities that can reverse fraudulant transactions and the like. The "double spend" problem refers to a problem in distributed systems, not applied security.
Bitcoin wouldn't work without it - sure, it's a building block, but the core innovation behind Bitcoin is not asymmetric crypto. The parent comment was implying that using asymmetric crypto in finance would solve problems with security and fraud, when in truth, asymmetric crypto has already been in use since well before Bitcoin came along, and is an important technology but has not magically solved all our security problems. There are multiple separate things being conflated here in incorrect ways.
Asymmetric cryptography is a completely separate, much older technology that has nothing directly to do with cryptocurrencies.
Furthermore, Bitcoin does nothing to solve the kind of fraud problems you are talking about, and in fact makes the consequences of them much worse, since you no longer have a central authorities that can reverse fraudulant transactions and the like. The "double spend" problem refers to a problem in distributed systems, not applied security.