These two things are good enough for inclusion in many Cubes already, but then it also has sort of a combo potential with the flashback ability
Starter tip: Hold mana open for instants if you suspect shenanigans
Youll usually see this card in EDH decks that are focused on this strategy (Aurelia, the Warleader, Velomachus Lorehold)
So for example, Mikus Spark reprints Chandras Ignition, Miku, Lost but Singing is a reprint of Azusa, Lost but Singing and Miku, the Renowned repurposes Feather, the Redeemed
If it would be dealt damage, remove that many +1/+1 counters instead
Of course, character cards alone wont cut it in a discard deckyou need action cards to back it up too