Like Settle the Wreckage, this card is at its best when an opponent attacks you with a bunch of creatures
Mix low, mid, and a couple of high-cost cards so you always have a play
If you want to dig further into calculating EV for a specific box, you can utilize resources like MTGStocks or check out the youtube video below, which does a great job of explaining a few other details you may want to consider when calculating expected value
This certainly got a load more powerful with the printing of Torrential Gearhulk, but it was plenty good enough before
Teferi, Temporal Pilgrim Card advantage is king A lot of planeswalkers are strong, and a lot of Teferi planeswalkers are really strong
Belt of Giant Strength lets you practice some addition and subtraction in the best ways possible