What is the purpose of the Mahayana 'emptiness' doctrine?

Another naive question... Further to e.g. [this answer](https://buddhism.stackexchange.com/a/26040/254) , which may be an overview of **what** Mahayana teaches about emptiness, my question is **why** does Mahayana teach that? I gather that the *purpose* of the anatta doctrine in the Pali canon is, at least partly if not wholly, to end suffering etc. -- e.g. [MN 22](https://suttacentral.net/mn22/en/sujato) : > It would make sense to grasp at a doctrine of self that didn’t give rise to sorrow, lamentation, pain, sadness, and distress. *Taṃ, bhikkhave, attavādupādānaṃ upādiyetha, yaṃsa attavādupādānaṃ upādiyato na uppajjeyyuṃ sokaparidevadukkhadomanassupāyāsā*. > But do you see any such doctrine of self? *Passatha no tumhe, bhikkhave, taṃ attavādupādānaṃ yaṃsa attavādupādānaṃ upādiyato na uppajjeyyuṃ sokaparidevadukkhadomanassupāyāsā”ti?* > No, sir. *No hetaṃ, bhante.* > Good, mendicants! *Sādhu, bhikkhave.* > I also can’t see any such doctrine of self. *Ahampi kho taṃ, bhikkhave, attavādupādānaṃ na samanupassāmi yaṃsa attavādupādānaṃ upādiyato na uppajjeyyuṃ sokaparidevadukkhadomanassupāyāsā.* What is the benefit if any of the emptiness doctrine? Does it have a "soteriological" purpose? How does that work, i.e. what is the mechanism by which the doctrine is beneficial? Or is it meant to be simply true, an observation or description of fact, without benefit?