good topic for discussion. I know such people who systematically donate to games and buy various boxes to get skins, they look very harmless and I would not say that the amounts that they spend on video games are large and I would rather not compare this with gambling addiction, if the first type of player is more likely to simply be disappointed that he does not get the desired item for a long time, then the second type of player who is gambling will try to compensate for the losses by receiving even greater losses.
My child uses that donate system to buy skins and game currency or lives. I am talking about Candy Crash game and Roblox. I see nothing bad from such kind of donations. It gives a little different game experience, allows not to look similar to other user and their avatars. But there are games where you pay to spin wheel and open box, get skin or bonus - I think that such in-game purchases are total gambling. And they are way more addictive than regular gambling, because these cases dont cost much and it is hard for children to realize how much they are spending.