Their being classified a part of the "Vedic" literature is not borne out by linguistic analysis, even though tradition claims it to be.
They post-date the actual Vedas themselves by centuries. The language used in most of them does not contain nearly as much irregularity as the Vedic language nor its pitch accent system - it's on its way to being a refined liturgical language, not a common man's language as the Vedic language was.
And the subject matter contained in them reflect that of the elites of a far more settled and stratified society (vs the more nomadic tribal culture of the Vedas). They are no more representative of Hinduism than their contemporary folk traditions, just as St. Augustine is no more representative of Catholicism than folk Catholicism where blessings are sought for mundane topics like health and prosperity.
No doubt, both groups of literature are incredible, but to lump them into one is incorrect, even if that is the tradition.