Technology is almost advancing too quickly for our own good. If you really think about it, the amount of technological advances in the last 20 years alone, is probably more than the past 100 years combined...
The nuke was really the epitome of this truth. What will the next super-weapon be? What will the world look like in the post-atomic era, if we don't find a way to stop governing our world with violence and start governing it with reason?
The BTC in my brain is for long term storage. By the time I need to spend it, there will be wearable tech that detects my unique heartbeat (we all have unique heartbeats) to secure my transactions.
Oh no! your wearable tech contains a backdoor that transmits your heartbeat data to an attacker each time your heart beats. Bye bye BTC...
Hmm, that's actually a fair point, and scary thought. Fine then, 1 brain wallet -> 50 paper wallets.