B) It's pellucidly clear that holding bitcoin is dangerous in the same way that holding gold is -- i.e. it can be stolen. In fact, it looks like the carrying costs may actually be higher.
B) You can take your bitcoin, encrypt it, and put it anywhere on the Internet in plain sight, and then hold the encryption key in your pocket, or in your head. Totally safe, especially against the real threat, border security. Bitcoin is far easier to physically secure than gold is. What's difficult is securing it in a manner that also makes it easy to do business with it.
> You can take your bitcoin ...
Perhaps you could, but people generally don't. So in terms of actual risk and carrying costs and how that relates to potential market cap, your foolproof system is rather irrelevant.
These problems are mostly solved for "us", on hacker news. You might even say that it's easy to solve. Yet the status quo for anything digital around me is "hello123" as a password, and panic when having to re-enter the gmail password on that new iDevice because it has long been forgotten and neither "hello123" nor "hello321" worked.