True, but is there a better alternative for a portable device with a slow, unreliable or expensive connection (such as a smart phone, possibly roaming in a foreign country)? There are plenty of situations where a person may wish to be able to spend some currency, but not have the ability to maintain a stable connection to a P2P network. For Bitcoin to succeed as a general purpose currency, I think there will be a need to address such use cases, even if they're limited to infrequent cases where a user might accept elevated risk while spending a small amount of "pocket change".