All cryptocurrencies are eventually tied to a “private” key. You lose this key, and the funds are gone, forever. Millions worth of bitcoins have disappeared from the circulation due to lost keys. You can memorize the key by mapping it into passphrase consisting of memorizable words but if you forget that, like many others, the coins are unrecoverable. An alternative is to trust a centralized service like Coinbase, but then all the benefits of investing in a decentralized currency are gone. Lastly, one can use a hardware wallet, but again, if you lose the wallet, the key is lost. If you keep the key on your device, then a malware might target and try to steal it someday. Thus, even if you are bullish on cryptocurrencies, there are no good decentralized ways of holding a significant chunk of your net worth in cryptocurrencies.
...