I've been test driving the new system (ID Austra/Digitales Amt app) for a few months now and for the most part it seems to be a replacement for the old "Handysignatur" system that let you digitally log in and sign PDF documents. This system was and is much better than you needing to manage your own certificates and made the whole thing accessible.
The new app basically just unifies various online forms that were already present, such as changing your address registration. None of this stuff is new and you already needed to sign in with Handysignatur to use these forms online anyway. More importantly, nobody in Austria forces you to use these services, you can file literally all of these on paper. They even have a service to fill out the forms digitally and then print them. The app also doesn't request stuff like location information and doesn't do anything nafarious as far as I can tell. It is also worth noting that ID Austria supports FIDO instead of a phone too.
The new app basically just unifies various online forms that were already present, such as changing your address registration. None of this stuff is new and you already needed to sign in with Handysignatur to use these forms online anyway. More importantly, nobody in Austria forces you to use these services, you can file literally all of these on paper. They even have a service to fill out the forms digitally and then print them. The app also doesn't request stuff like location information and doesn't do anything nafarious as far as I can tell. It is also worth noting that ID Austria supports FIDO instead of a phone too.