For Granite it would have been great just to get him some more live pitching before he closes up shop for the year. I think as far as the parent clubs are concerned, the purpose of the AFL is mainly to extend the season for certain guys.
So some players you'd think would make sense probably won't go because they've played a ton (Lewis, Kirilloff, Rooker) or they don't need to increase their innings any farther (Graterol, Jax?). Then some other less obvious guys will go simply because these teams still have to be functional (maybe a middle infielder like Alex Perez or a catcher who can play multiple positions like Mitchell Kranson).
Well said, although I think Kirilloff might still be a candidate due to him missing last year. Then again, I'm often known to be wrong and I sometimes have been known to eat crayons .