Yes, like you can lose your treasure by forgetting where you buried it. Or you can lose your silver when an accidental fire melts your palace into slag. Or you can lose your wheat harvest to mold! Self-storage is the default way of holding wealth, not a new one. And it's a tradeoff that people will always choose to make as long as personal wealth exists.
Among the innumerable problems with cryptocurrency, this is not one of them.