While it may appear to be a smaller-scaled threat, Blighted Agent can be buffed by spells akin to Giant Growth, that for one mana, provide a creature with +3/+3 until the end of turn
Face up/face down refers to double-faced cards
Fierce Guardianship is one such counterspell that sweetens the deal by eliminating its mana cost if your commander is on the board--something that will likely be the case when you want to cast this spell anyway
For example, Annihilate will be card advantage if it resolves normally targeting a creature an opponent controlsyou lose one card from your hand but you also draw a card, for a net gain of zero cards, and your opponent loses one card, so you're up one card relative to them
No matter what, this card is excellent and should swing a lot of games in your favor
That is counterintuitive when your goal is making something more accessible