I got this product in the MM tool kit and was thoroughly confused. Eventually, I grew to learn the usefulness of the tool.
I bite my nails A LOT. They are extremely short and that makes it virtually impossibly to peel things off (such as already stuck stickers) So whenever I misplace a sticker or embellishment that is small, I use the piercer to get it off for me!
Also, when I first got my cricut I was going to buy the spatula (that gets the die cuts off the page) but I soon realized that I could use the piercer to get underneath the edges of each letter/shape really easily no matter the size and it pulls it right off!
Great product, so many uses!