Play is definitely needed for growth. It's true for kids, it's still true for so called grown ups.

There will always be some design and some testing. The intensity of both activities needs to be properly managed over time though.

On specialized and formalized domains like this it might lead to something interesting. That said there's a tension with the fact that it doesn't know when it doesn't know which might be problematic. Also I wonder how it fares compared to computational models like WolframAlpha. In the end very formal domains like this have large knowledge bases already available.

This is a bad case of content moderation if it gets presented to users like this... but Google is not going to leave advertisement money on the table. The way browsers changed in recent years also make this kind of deceptions easier (harder to check certificates, hard to spot punycoding).