We have here a deck called MONARCH DECK
If youre playing at higher brackets especially B5 or cEDH youll know how important stack wars can be
If you're in the middle of a duel and you pull off a nice play, gauge the reaction of your friend
Or, they can go for something different like Alluring Mirror Split (which will special summon a Harpie monster card from the deck if one is destroyed by battle), Harpie's Feather Rest (which allows the player to shuffle three Harpie monster cards from the graveyard into the deck and draw two cards), or even Harpie's Hunting Ground as mentioned earlier
The Mana Rig, Alquist Proft, Master Sleuth, Nin, the Pain Artist, Tameshi, Reality Architect, and many others can really make use of this discounted double-activation sweet spot
They can go under the radar, and still surprise against other Decks with their powerful banishment effects