Contrary to random pieces falling onto earth they are from a specific astroid and not impacted by earth atmosphere (which burns those stones quite a bit) Thus

Contrary to random pieces falling onto earth they are from a specific astroid and not impacted by earth atmosphere (which burns those stones quite a bit) Thus they potentially reveal more details and allow comparison with planets and other objects, which might help to identify the origin of the astroid and in turn be a piece in the big story how our solar system came together.