> If X works great as the short-term transfer medium, then it keeps/raises in value, and becomes good also as a long-term store of value. This seems very simpl

> If X works great as the short-term transfer medium, then it keeps/raises in value, and becomes good also as a long-term store of value. This seems very simplistic. Is there evidence that the value of a currency is directly related to transactional volume? It's obviously not the case that that is the sole factor. Even if that were true, your point is contradictory. As you say, 'If X starts to fail as the transfer medium, then the value collapses as well', and there's nothing that guarantees Bitcoin will become a serious transactional currency, or if it does, won't be supplanted by something else. Under no circumstances is this a place where you'd want to store substantial savings that weren't set aside for speculation.