You can look at the risk of what it's preventing (covid has already killed ~1700 people per million in the US), or compare to other activities and risk levels.
Relative risk comparisons between different activities are often not useful. For example, the risk of shark-death at the beach might look alarming when compared to my risk of shark-death-at-home, but actually it's vanishingly unlikely.
But what about the risk of heart inflammation from Covid-19 in that age group, possibly with no other Covid symptoms?
This is a big assumption. It could also be that it becomes part of the virus background infections we all deal with except that it is high risk if you get it the first time.
When looking that the risk of an non vaccinated individual catching Covid today keep in mind that a lot of people have been vaccinated and the incidence numbers de-facto refer to incidences of the non vaccinated part of the population which would justify a smaller denominator than used (whole population).
That said, there is no guarantee that herd immunity will ever be reached at least in the US. If herd immunity isn't reached then it's basically guaranteed you'll get it eventually as the disease becomes a "background disease".
Also, underreporting is a factor - not everyone knows about VAERS, not everyone goes to the Dr. for chest pain etc.
I agree it's favorable, but it's important to understand the effects of any medicine on subgroups of a treatment population.
Observed (O) cases in that age group: 283
Expected (E) cases in that age group: 10-102
So at least double the top of the confidence interval, for expected.