It would be useful to be able to apply a discount (monetary or percentage) to a total overall cart vs having to apply a small percentage or dollar amount to specific items.
It would be nice to be able to include what items must be in the cart for the discount to be applied, but to not have it tied to each item.

Ie. I want to offer a $10 discount for three items purchased, but they have the option of six items to choose from. So I end up giving a $3.33 discount on each item, whereas having the ten dollars go to the cart total would be more convenient.