you would really prefer username/password login? I just hate that system. the current system is so elegant. I was thinking of emailing a code- which you type it, to help with people on different devices.
You dont have to add username and passwords and I dont like that system, but you can send longer term codes that could work more than one time.
Default option can stay, but sometimes I cant access my email address or I am using different device, so it is impossible to use password manager for login.