[JshWright]

Which is great if you have a printer (and are near it when you're signing up for the account, and remember to do it, and remember to put it in your safe, etc...). Just because it's the easiest way currently doesn't mean there isn't substantial room for improvement in the usability of passwordless systems. Most users aren't going to go to the trouble of printing something out like that.

[eco]

You can also use a pen though your point on ease stands.