You may have misinterpreted my comment. I did not say whether I think cryptocurrency is a good currency. For many of the reasons you stated, I think it is a bad one. However, I wasn't rating the four options (cash, banks, CBDCs, other cryptocurrencies) as best currencies, but only on the "how easy is it to take from you by force if you assume that the force concerned has complete legal authority" index. I don't think that's a very important index, but it was the point others brought up, so I was using that metric.
I don't have or want any cryptocurrency, but some of your criticism isn't global to the concept. For example, the energy requirements and privacy problems are both entirely accurate descriptions of Bitcoin and many ones like it, and both are big problems to making them useful for anything. However, they do not cover all currencies. There are privacy-focused ones like Monero which don't make it easy to track transactions the way that Bitcoin does. Monero is also easier to mine on commodity hardware, which is usually considered a bad thing because it's what cryptomining malware tends to be mining. I'm not sure how well Monero scales because, since I have no interest in owning any, I haven't bothered to learn all the details. It's possible that it would also fail badly if it became more popular. However, it's useful to keep in mind whether the complaints you have are intrinsic to the concept of cryptocurrency or not.
For example, the dodgy exchanges are a big problem, but that's a legal thing. If some government chose to regulate them like banks, including mandatory insurance programs like the FDIC does, they could have similar security to banks. The exchanges don't want it because they want to get as much money as fast as possible, but they could be required to take those steps. Whether the companies handling the commodity are trustworthy isn't related to what they're storing, but the oversight of their operations, regulations they must follow, and their accountability for failure to follow them.