What is the advantage or the features of distinguishing a variant product and product provided by Hybris Out of the box? Can't we create a custom variant product model?

Besides the need to display Other variants associated to a given base product , why should we model a product as variant product? Can't we create a model called 'Variant Product' extending product model?

What is the advantage or the features of distinguishing a variant product and product provided by Hybris Out of the box?