Better question is, has this ever been done well? The only instances of "looks cute but is actually mature" I've seen is when the cute look isn't intended to be shocking or subversive but is genuinely just the author liking it and thinking its fun to create it in, and there's no sense that you're meant to be "tricked" by its appearances until it jumps and "shocks" you with it
Every game that DOES try and do that just ends up being shit, partially because it relies so much of the surprise that it has nothing else to offer, and partially because the idea itself is so bland yet so appealing to bad normalfag writers that they can't come up with anything else

You also effectively can't market such a game
Market it as cute and innocent and forego the scaaaaary or mature part, and sure, people will be shocked, but they won't like it since they most likely just want an actually cute game whereas people who DO want something mature or horrific won't find it... That, and nowadays you even risk being le cancellede for giving people le trauma
Market it as scary and shocking, and you lose all the shock value, meaning your game can't rely on it anymore and now has to actually be good DESPITE of it, not just FOR it, which most of these creators don't know how to do
So really the only audience left for these games are screamertubers who will watch, er.. I mean play your game... Pretend not to know it gets dark despite seeing the tags and then screech about it performatively

What's the point? Who needs it?