Unlike most counterspells, it is not purely reactive you can use this card as an instant speed mana sink in the opponents end step to generate a huge threat, or as a combat trick to force through sudden lethal damage after blocks are declared
You can win real rewards through these events by selling the prizes you get, so if thats something that appeals to you then this is a great way to play the format
It also tells you the rarity of the card
Minsc & Boo, Timeless Heroes I hesitate to call the second ability on Minsc & Boo, Timeless Heroes an ultimate, but it works so well as a sacrifice outlet that burns targets and gives you cards
For example, if a 4/4 creature an opponent controls is dealt 2 damage by a spell you control and later that turn is dealt 3 damage by a spell another player controls, Aegar's ability will trigger