The ending doesn't quite come together in a satisfying way. It would have been better if we saw the boy getting the prize money and his life improving a little, and perhaps a little bit of actual romance between the MC and the boy - like a bit of tension there or something... or heck, it could have just between between her card playing persona and him, rather than her usual self.
Still cute, I'd give it a chance if they made it a serious, though I think they'd either have to move past the card game gimmick and expand out into other games/framing-devices, or they need to really expand on how the card game works, because it feels really underdeveloped right now... though given it's just a oneshot, so it's no surprise.