It's not like they can really avoid it. AI assisted tools will become a standard in the future ("productivity has to go up" after all) and there's a good chance Valve already received some feedback from AAA publishers on that matter, since they'll be the main players utilizing such tech.
The good thing here is the exsitance of a disclaimer on store pages, as it will allow people to decide for themselves, and the ability to report content straight from in-game overlay.
I'll add that a blanket ban isn't necessarily a positive thing, either. AI could be a component of developing unique NPCs, evolving bosses, changing economies, missions/quests, or procedurally generated levels (for example).
Obviously, at least some of that content would still need to pass human play testing, so it's not like humans would be completely removed, but imagine if players had gameplay experiences that were entirely unique to them or changed based on non-RNG factors.
I agree, though, that reporting the use of AI and how it's utilized is important for people to make informed decisions about how they spend their money.
Personally I'd love to see a new take on Daggerfall using AI for features you mentioned (though it would have to be an "all in" affair as Bethesda's approach to randomly generated content these days is... not particularly impressive).