We already have a traffic light system on foods and it is largely ignored, partly because few people have the time and energy but also because you have to look at your diet as a whole and not judge it by individual items. I also think these UPF studies have a bit of a conservative agenda.
Why do people eat more processed food? Because there isn’t a homemaker spending hours a day preparing meals as a full time job. Proceesed and convenience foods are massively egalitarian and I think let more people join the workforce.
Literally none of that requires an nft. Standardising items between games also makes zero sense, games by their nature are very different technically and would require the items to be implemented in every game, which wouldn’t happen.