Oh, I remember 194x and Gauntlet being a bit abusive and pay-to-win. ;)

I disagree with you. I don't think that pay-by-usage is inherently bad, for adults or kids.

I also feel like... it's probably best if one doesn't encounter these kinds of things as an adult for the first time. What's better to learn moderation with?

My kids (11, 9, 6) have, so far, largely shrugged off microtransaction things and think they're kinda dumb... But they've spent maybe 10% of their discretionary money since birth on Pokemon cards, which scratches many of the same itches. I don't feel like A) it's bad for them, or B) that they're going to look back at the time and money spent and regret it. But they have regretted spending a little bit on Pokemon cards that they'd later rather have spent on something else, and that's a great lesson.