Fast transfer, agreed. Cost per transaction is currently between 10 and 20 dollars and has been close to 100 dollars. I don't know what a wire transfer costs but I don't think the advantage is huge if you are only transferring a couple hundred or a few thousand dollars. Safe and secure store - taking malware, hacked exchanges, price fluctuations and the like into account, I am not sure it looks really bright. Future killer apps - let's talk again, when they are real. And tipping, for example, does not look like it could work - transactions are way to expensive to be used to tip a dollar. And when it comes to unbanked people I am not sure that it would be better or easier for them to adopt Bitcoin instead of a traditional banking system.