Matrix Cloner is insanely fast compared to Cloner Object. That's why Octane, RedShift, and Cycles4D allow you to add a tag to the Matrix Cloner, which let's you specify what each point should render like (pointing to a Cube for instance, or a corn of sand).
Arnold already has this ability with x-particles. When you add an Arnold parameter tag an XP-emitter, you can choose which Geometry it should render from. But you can't to that with the Matrix Object. Any chance we could get this?
That simple addition would allow for a lot of new exciting use cases like scattering sand or flowers etc.
Can't you do that natively with an Instance or Cloner in Multi-Instance mode?
You can use the Mesh Particles tag on a Matrix object to instance points. Note that there is a bug in the current version (2.6.1.4) and the IPR does not update when you change or animate the Matrix object. This will be fixed in the next release.