system
Given the following post, respond as if you're commenting on Reddit:
human
I'm sorry, but nobody has actually told me what cryptocurrencies are used for.

Is it purely an investment now?  I, with my limited idea of economics, do not see a reason to keep it except for investing or hobby purposes. I know that it was supposed to replace banks or something, but what does that even mean?
gpt
Currently, almost all the value of almost all crypto currencies is based on investor speculation. More materially, the fundamental value of cryptos is the electronic ledger and the ability to privately and securely transact.