And again, what the parent says in untrue. You can sign documents with your phone and still take part of the expiring public tender he describes.
So if a person doesn't already have Mobile-ID and their ID-Card certs are blocked they can't get a Mobile-ID and thus they can't access any digital government services.
It's not like this is purely theoretical - large number of Estonian Id-Card will have their certs blocked and not everyone has Mobile-ID.
2. Mobile-ID requires you to pay for signing up and after that, 1€/month to your mobile provider.