In the past, things like age verification required users to upload a scan or photo, and someone had to verify it. Because that was too much work for the platform operators, they didn't do it (or only with the banner "Are you over 18?").

With the e-ID instead, this will be much simpler to implement. And I expect it to become much more widespread in the future.

https://news.ycombinator.com/item?id=41608810

Also, the UK gov has already said there will be solutions for old people/time travellers/the Amish etc without phones. Nobody is going to force anybody to buy a phone.

Companies do have to accept a physical card as well, but only if you appear physically at the companies doors. Otherwise, that statement was kind of deceptive in my opinion because there will be a lot of pressure to get one. They also decided to make it free, which shows they probably want to achieve a high adoption.