There are situations where using a password can be a little more convenient, for instance if you like to connect to the machine from random computers and you do

There are situations where using a password can be a little more convenient, for instance if you like to connect to the machine from random computers and you don't want to/can't carry your private key with you all the time. Obviously it's not the best security-wise, using a hardware token containing the key or even OTPs are probably a better solution.