The author seemingly uses minimizing deaths as the only measure of benefit; I don’t see a discussion of minimizing or avoiding what have been called long-COVID effects.
Honestly I have no idea if children suffer from long-COVID: either how badly or what percentage of cases but a cursory search suggests that they do. Certainly I would expect that it’s easier to use a binary metric like death in a risk-benefit analysis but I was hoping a professional in the field would have some way to account for these other risks.