Kinder Surprise is an ordinary milk chocolate poured and packaged in the shape of an egg. So it has all the properties of milk chocolate - good and bad. The harm is that chocolate is a carbohydrate, the rapid consumption of which can lead to excess weight.
If you believe the numerous discussions on the Internet, mineral oils of aromatic hydrocarbons were found in Kinder Surprise, that is, oil refined products. And the frequent consumption of these substances can lead to the development of oncology.
Some distrust of this news is caused by the fact that Kinder Surprise has been on sale for more than a decade, and only recently they started talking about harmful substances in its composition. And there is a possibility that this is anti-advertising launched by competitors. Still, it's better not to risk it.