What if you have US$10,000 in your bitcoin wallet on your laptop? Is that the same as US$10,000 worth of collectable pins in your suitcase, or the same as US$10,000 worth of code/IP on your laptop (which I can't imagine anyone declaring in customs)?
Then it's the same as any other asset you have access to but isn't liquid, so it's not an interesting question when you're talking about how much you can take through customs without declaring it.