Eternal formats have long defined their identity and play patterns around breaking the mana curve, and cheap (or free) counterspells are one of the only things that can keep such explosiveness balanced
Cons: Time-consuming (research, buying cards, testing), can get expensive if you dont set a budget, steeper learning curve for new players, and your first few brews might not be world-beaters
Pair it with something that removes -1/-1 counters or adds +1/+1 counters when it comes into play and a free sacrifice outlet like Ashnod's Altar and this creature goes infinite in so many ways
And hey, maybe Ill get some cool keepsakes along the way
PLEASE EXAMINE ALL PHOTOS THOROUGHLY
The Council of Four Upgrades: Howling Mine, Dictate of Kruphix, and Kami of the Crescent Moon are all staples