Exactly, I've had same thoughts going in my head, the theives would've taken his jewelries, valueable items or even fiat money but they chose to beat him out of his consciousness and ask him to transfer his Bitcoin when he was back to his conscious state, which means they're fully informed about his worth in bitcoin, the world has birthed cruel societies lately and people ought to take precautions and safeguard themselves and if you got a spare money spend it on security and well being instead of leaving an extravagant lifestyle, that would attract attention.

 I'm pretty sure the theives would have some knowledge about Bitcoin before carry out that operation, else they wouldn't have been able to figure out how to carry the transaction or even have a wallet to receive the Bitcoin not to talk of knowing the right crypto asset to rob.