Not everyone will have played it already. If I’m a new buyer and I see one version and another version that’s the same but looks better, then yeah I’m gonna buy the one that looks better.
There are daily challenges and things like that which is what I would refer to as online play. Not that crazy imho of you’ve put thousands of hours into vanilla solitaire that you may welcome something to spice it up.
I can’t speak for other people, I don’t even play solitaire. Realistically, I imagine most people get new PCs with newer Windows versions and play whatever solitaire is on there.
This isn’t really new. Solitaire has had ads for over a decade now since Windows 8, and there is a monthly premium subscription to remove them. As I understand it they also don’t show during offline play, but might be wrong about that.