I think this is more of a defence against scammers honestly, with a convincing enough scam you could make valve belive an account holder was dead and you're a family member wanting to transfer their account to yours.

Hell, I saw my dead friend's account message me in Russian, contacted support about it, and all they could do was remove the hacker's access, not even lock or delete that account.

And how could they? Unless you have your full name, address, and other identifying information somewhere on your account (strongly ill-advised, obviously) Valve can't cross check it with a death certificate and take action, for all they know you could be cooperating with the hacker or submitting fake information to "prank" your friend by getting their account removed.

Allowing account transfers would open a whole new can of worms.

Just write down the password and login if you know you're going to go. I don't think Valve under Gabe would have issues with that. Though I do worry for its future