Why it worked
The video leverages the high visual appeal of a large quantity of a popular, recognizable consumer product, creating a satisfying 'unboxing' or collection aesthetic that performs well with younger audiences.
Product placement
Kinder Joy (a brand of chocolate eggs with toys inside). It ACTS because the children are interacting with the product, opening the packaging, and collecting the toys inside, which is the primary activity of the video. Removing the product would change the video entirely as it is the sole focus of the interaction.