When I say it is insignificant, I'm saying that it is not nearly as big of a problem as the other risks from COVID. When a million people have died from COVID, and millions of children have been infected with COVID, I view any COVID symptom that affects less than 1000 people worldwide as insignificant relative that.
Now it is very possible that we will realize that over the period of years, some significant percentage of children with COVID are affected by this. But so far the data doesn't support this.