At least in NGNL and Kakegurui the characters aren't dumb.
Here, The MC who doesn't want to use his talent but use it the first 5 second he enter the school, the "comic relief" who's so dumb that even after using all her family's economy and losing every fricking games still want to stay in the school without trying to improve in any way other than rely on pure luck... The others characters are correct, but when 2 of 3 main characters are dumb it doesn't bode well.
Still, the story seems interesting... Will keep an eye on it.