I've never heard of a frozen keyboard. That is definitely not an issue to worry about every single time anyway.

Plus when it works you need a second press to turn it back off before entering the password. Way too much work.

I usually use the up key as that is one of the few buttons I know of that will open the password field (I'm assuming down also works, but I haven't tried many others). I usually turn my monitor off (can't just leave it on as it's in my room and if a cat moves their ear too quickly that will wake up the screen and I can't have that while I'm comfortable in bed) at night, so the first time I use it in a day I will turn it on, smack the up arrow and the login screen is gone before the screen turns on all the way. Which is a little sad I don't get to see it much since I did pick out a theme and background for it, but can't be helped.