It's normal for those who like spending in the game to see how strong they can get.
IMO, it's not really a gamble. It's more of they have money to spend and it gives them a pleasure to see their characters trying to be on top.
The thing is Gacha game does not deliver the product directly unlike those games that make their items have a flat price. Gacha is like taking chance to get an item with a certain percentage. The higher tier the item is the lesser percentage a player can get it. The core mechanics of gacha as one of the replies stated is wagering an amount of money and having a chance to get the desired item. So it includes money, luck, and chance which resembles gambling.
Before, we spend money on MMORPG just so we can get in the game. It will not even make us strong.
Now, gacha games are mostly free to play but to feel the essence of the game you will need to spend real money and buy things that cannot be received just by grinding.
The downside, you cannot sell them. There's no profit back so it's not a gamble.
Gacha games aren't free to play. A player needs to spend money to activate gacha games. the game integrated with gacha game may be free to play but the gacha games for the item are not. The item Being non-transferable is the leeway this game developer has to circumvent the law against gambling.
I sure have become addicted to some Gacha games and in the past, I have played a series of games that need Gacha real money to get what kind of item, hero, or secret something that you want, and that includes a huge amount of RNG kind of slot or wheel that you will need to play with real money or game money and will be in random order, for me it is very hard to win you don't put a lot of money in the game, that is why I call this time of games as pay to win, some game that I play and here is the list,
I was once got hooked in a game that has Gacha in it. And it is really hard to get the premium item, mostly you get trash items that has no value in-game at all.