> but this is also clearly a increased barrier.
If there's a simple piece of software that can be installed, it's not meaningfully increasing the barrier. Also, there are negative consequences to introducing "rules that you're expected to break" like this. It makes the law unserious.
If it costs money that is definitely a barrier for a child. And apps can be as well, as a parent its easier to control what apps is installed than webpages visited.
Advertisers. Naturally someone who feels excluded or unable to compete on cleaner markets will offer the portal for people who don't have a regular id and if the ads on those portals do best if they are for toys then those are the ads they will sell.