That's the debate in the article body.

Less hedonistic meaning they are having less sex and so fewer unintended and teenage pregnancies, less drinking and drugs and so less violence and anti-social behavior, better relations with the parents and in particular their fathers, and more pursuing further education.

Basically every metric of bad behavior that used to be a cause of concern for 80s and 90s teenagers is across the board at record lows for the current generation of teenagers.

Downside is they are more likely to be depressed, stressed, sexless and lonely with weak connections to their age peers.