Yeah, quite ahead in terms of making anonymous phone numbers illegal and requiring the government to know your phone number.
And if you don't want to use a smartphone, ID Austria does not work with regular FIDO security keys, you need special ones. Same for the old SmartCard system which didn't work without government-mandated malware.
It seems to imply that the already existing way of authenticating via eID, which is the auth chip present on our ID cards, will still work, if I read it correctly? I understand OP's link to refer to a new, alternative system, that can be used without the ID card.
But take this with a grain of salt, I'm not very well informed about the whole topic.