It's not a very large tiara but for a young princess quite suitable and wearable. Im not a big fan of the design with the middle line through the piece.
Still the princess has her own tiara and it's bigger than the one Claire got for her wedding. The Belgian Royal family never gave Astrid a tiara so things are looking up. We can expect future brides of Gabriel and Emmanuel to receive pieces too. That would leave Mathilde's jewels to Elisabeth and we can slowly see a crowncollection being formed.

In time she could have:

9 Provinces tiara
Wolfers necklace/tiara
Laurel tiara
Vestey tiara
Diamond brooch
and several sets of diamond earrings

Still nothing grand but at least a little more than her mother and grandmother had at their disposal.

I do lament the fact that the jewels owned by Queen Elisabeth, Queen Astrid, Queen Fabiola, the count of Flanders and the pieces sold by the daughters of Queen Marie-Jose are no longer part of the collection.