Cryptocurrency is a useful technology that has some real-world use cases - for example, living in Russia, I use it to circumvent sanctions to donate to some of the crypto-friendly creators, pay for a VPS abroad, and I keep calm knowing I can transfer money to my relatives abroad.

However, it is obviously not the answer to how we should build the financial system. The problem is not environment, actually - many Proof-of-Stake blockchains allow to transfer crypto with minimal environmental impact - but the poor on-chain regulation (including taxation, too) and potentially excessive infrastructure, as well as little protections against malicious and fraudulent actors.

Besides, inability to control emission, while helping maintain the value of the currency over the long run, also means that many interventions that can save economy in a crisis are simply not available. And a deflationary nature is known to cause bubbles.