I wouldn't consider gachas to be "actual games" (sue me), but yeah, they do tend to have way more complex gameplay and graphics than the timewaster freemium games of yore. Genshin Impact is essentially a single-player MMO, it has an open world and lots of characters and different weapons etc etc.
The "general phone audience" is some 5 billion people. If even 10% of them want to play games, on what is in the current year likely to be their primary if not only computer, that's already a market segment of 500 million. It wouldn't honestly surprise me if the number is closer to 15 or 20%, mobile gaming is extremely popular.
I think a lot of HN users, living in our own PC-oriented bubble, may not have realised the world has completely passed PCs by and that smartphones are the personal computers of the current generation. While PS5 and Switch each have about 100-150 million in sales, there are an estimated 3 billion mobile game players. Are a majority of those "mobile game players" playing Flappy Bird, sure. But again, even 10% of that number being interested in "real games" would outnumber PS5 and Switch players combined. Fortnite and PUBG each have hundreds of millions of active users, most are on console but around 20% appear to be on mobile from a quick search. Genshin Impact also has tens of of millions MAU, a non-neglible percentage of which are mobile players. There are hundreds of millions of people for whom being able to play 3D games on their phone matters.
