I'm all for this. Not only would it make logging in to the forums via my phone more feasible, it'd allow me to show other people how amazing this game looks when I bring my laptop around (I always leave my actual authenticator at home because I'm scared to death of losing it, even though it has a keychain ring).

Also, it would give more incentive to people who maybe don't want an extra piece of hardware, but do want a more secure account, since less hacking benefits everyone involved...well, except RMTs, but who cares what they think =P.