Crypto meaning cryptography yes it's needed. If you a referencing bitcoin like technology used for money no they don't help here. Please enough with this "crypto" ignorance
We should get rid of them since they have no value. Personally I like them because they facilitate trade and finance on a global, immense scale and allow for decentralised price discovery and information distribution. But then does trade and finance have value?
..wait maybe money networks do have value
Not really. Countries define property rights and solve problems. Domestic overfishing is countries removing externalities and making them part of the market