Government software is usually low-quality, expensive procurement crap, often riddled with security holes, and an exercise in checkbox checking. UX and user friction can't be expressed as a verifiable clause in a procurement contract, so they're ignored.
Besides, every time EU governments tried to force smartphone manufacturers to pre-install government apps, the population freaked out over (unwarranted) surveillance concerns. This isn't something you can do without pre-installing apps (you don't want these APIs opened up because then attestation loses all meaning).
Not necessarily the company that locks out entire family because one of the family member jacked off on the chat with Gemini model.
The scenario it would prevent is that a government gets a filled in form with someone requesting unemployment benefits, or reimbursement for a medical procedure on account X ... and then government finds out after payment, later, in court, that the owner of the phone never agreed to it and it needs to pay it out again (because the claim, true or not, that a scammer initiated the payment agreement in some way rather than the owner). Same for business and agreeing to a loan and ...
It is NOT to protect you, the owner of the phone, against scammers (it does not really do that at all), it is to protect companies and especially governments AGAINST the owner of the phone. It is a way to fire most EU government employees by allowing automation that currently can't work because you can't legally trust phone and internet automation to be binding in court.
Because if it is the end user, the strong version of the argument would be as follows: The end user signs a document, baked in is an attestation that Google guarantees that this device is an approved Android device with a clean boot chain and a Chrome web browser. Then the end user contests the signature in court, either because they didn't understand what they signed, or they did not sign it at all, or did it under threat. How could the attestation help here?
I do not have experience with all EU countries, of course, but more than one, and nowhere is this an issue today. Countries use a wide variety of electronic identification, from soft certificates and mobile phones to smart cards. But as far as I know, all countries accept signatures made even with normal Windows PCs. You can contest a signed document in court for a multitude of reasons, but that's not specific to electronic signatures.
So they're just going to use the Apple/Google standards and declare the job done. So it's theater from all sides. Politicians will pretend this is a good solution because they don't want to spend real money, and they really want to tempt EU kids to get loans on their smartphones because, you know, in the EU you're protected from companies exploiting you. Of course, that just means governments will have to do it instead.