Yeah I thought so, too. But this does come with the pretty big benefit that the demo will have it's own reviews. Which is cool. I like that. And to be fair, they already showed up as their own entry in search results as if they had a page, they just then also went to the same page.
I think just having a tab (just below the game description) showing reviews and rating for demos and for the full game, without having a dedicated app ID, should be enough.
I don’t know, but this feels like a step back. I haven’t downloaded/played a demo since, like, 2005. There’s usually a gameplay video or review on YouTube that suffices before I purchase something. Ymmv :/