Exactly, I never got this about WeChat and WhatsApp. If I have my computer (which has a 4G connection) with me, I shouldn't need to carry my phone with me.
I usually run WhatsApp and WeChat inside Android virtual machines to solve this major design flaw.
My basic tenet of computing is that every device I own should be able to do ALL tasks that it is computationally capable of, without relying on other devices. When I'm sitting in front of a 4K screen with a massive multi-core CPU and GPU desktop, that I own, there is NO reason I should be be required to also have on my person a 6" dinky piece of junk just to operate the desktop. Every device should independently handle everything it is capable of.
So in my case the virtual machine can just run WhatsApp and I can completely leave my phone behind when I choose to carry my computer with me. Same thing for WeChat. I want my most powerful computers to be able to handle 100% of my personal tasks, not 99%.
Biometric MFA, I'm slightly more in support of.
I should be able to identify myself to any electronic system I own or control, using only what's in my mind and body, and nothing else. For now I use pretty much only passwords everywhere. With passwords I can walk and move freely about the world without worrying about losing stuff or forgetting to carry stuff. I always hated physical keys, because I forget them and lose them, and I hate anything that resembles a physical key in that respect.
I love combination locks to apartments and bicycles, by the way. You can head out the door and get around town with exactly nothing in your pocket. Maybe just a credit card to pay for food, at most. It's refreshingly simple and awesome to not have to carry stuff.
How entropic are combination locks? And vulnerable to picking - I've had to pick a 3-dial Realtor lock before in an emergency. It's easy with an aluminum-foil shim and Youtube instructions.
Quite entropic. And I use PBKDF-HMAC-SHA256 to generate other passwords from a master password on any machine I own without having to store or carry a database or keystore.
> How entropic are combination locks?
What is the attack vector here? A lot of key locks are easy to pick. My apartment door's key lock is a lot more insecure than some of the better combination locks out there.
If someone really wants to get in, they can smash the windows. At that point I think having a security camera system or alarm system would be a better investment.