Example 1:

Use dirt blocks when using the staff on a grass block and the player does not have any grass blocks in the inventory.

I can't come up with any more examples. But this one is very important. Makes filling those creeper craters around your starter base a lot easier and then it does not feel like you are in the middle of a WWI battlefield.

I second that - I think every mod using pick-a-block system should handle replacing Grass blocks with the basic dirt block - unless there is a mod that covers that already