As best I can tell I can only get extremely limited use out of the sand object.
-it only supports a sphereical shape absolutly-nothing else.

-it has a preferred size (compared to fluids) one fifth as large.

-it does not support Souce from Objects -so it will only emit a single ‘glob’
of sand. Even if retrofitted from a fluid setup which had this working.

-Sand Configure Object doesn't make a lot of useful sense to me.

Can I have it spawned from and arbitrary source geometry?
Can I have it emit continuously?
Or have I simply reached its limits?

BTW all tested in gold v9.1-all available docs have been checked.