If you worry about losing access over Steam guard. Don't. I lost my phone twice in the last 7 or so years. Support is very helpful for those cases. Just make sure to keep some proofs of ownership on tab just in case. Something you should be doing anyway if you take your accounts seriously.

That said, I wouldn't mind additional options for authentication, all I am saying is that the situation ain't that bad if your "papers" are in order.