We don't have any problem with satire and sarcasm as such, but on a large public forum like HN, with everything a mile wide and an inch deep, they are nearly always associated with really low-quality discussion.
Confidence. If enough people think rice bags or pressed and aged tea is money, then it is. At least you can eat rice and drink tea, bank notes or crypto hashes not so much.
No, commodity money typically has a variety of practical functions and its function in an exchange system is born out of necessity. Not arbitrarily because people want to start doing accounting that way. I don't understand why people repeat this. It's not clever or insightful, and worse it's definitely not correct. It's gravely concerning that presumably basically educated people tout this line without a second thought when it comes to cryptocurrency.
Cryptocurrency finds its value purely out of someone hoping someone else will be left holding the bag, not because it's useful.