We must return this to the notion of gambling which involves betting in a game. So in general if a game is without betting then it cannot be said to be gambling in my opinion, because it goes back to the basic understanding of gambling itself. And I agree that gambling carries risks, and if there is nothing at stake then what risks will we get, because we don't bet anything and will not lose anything from that game.
However, if it is based on personal opinion, of course there will always be different opinions from one to another.
Didn't gambling start back then when money was not created yet and other things were paid when a gambler lost? Because I remembered when I was young, I was still in elementary school, when I was playing with my friends in the text card battle of marvels super heroes, when I won, I got a card instead of winning and when I accumulated a lot of cards, I sell cards to my opponents or teammates to make money for a small coin.
Yep, gambling is very old from its origin, initially, people used to bet assets or commodities or whatever they had since there were no currencies in those times, and gambling has been evolving ever since that, and today, we have got casinos available right at our fingertips in our mobile phones or laptops and we don't even need to go out to gamble anymore.
Some people who gamble just for fun among friends or cousins or relatives still use things as a wager for bets when they are making bets against each other on a certain match or something, and it is pretty fun.