In Denmark a similar system (NemID) gave you a piece of paper with long alphanumeric codes to be used instead of the app. Now it's replaced by another system (MitID) which I haven't verified that supports those, but it's highly unlikely that it stopped supporting physical codes.
It's actually quite a good idea to have this, even if you have a smartphone, in case that you lose access to it temporarily.
It's actually quite a good idea to have this, even if you have a smartphone, in case that you lose access to it temporarily.