Tracking inventory on new variants

We noticed that when creating a new product with the mutation productSet, with the default or multiple variants, the variants that are created have “no inventory tracked”. Therefore, we then have to run the productVariantsBulkUpdate mutation, in order to set their inventory as tracked.

However, when we are adding new variants to already existing products with the mutation productSet, the new variants are being added in the product with their inventory already set to tracked. Why is this a feature?