Maybe because of the real gachapon which exists on Japan for decades and it's the reason why gacha games are called like that. If you don't know, gachapon is this:
There's many of those and different places of Japan where you put money and you get something random. The same principle is used on mobile games, which is why it's called gacha. If you ask me, in Japan we see gacha being more well received by people because gachapon is already normalized for decades, so since gacha is similar, it's basically the same type of people that spend money to get what they want and all.
