This restriction keeps the format balanced and preserves the legacy of these cards
Hexproof Shroud says, " Nobody can target this permanent, not even you ." Meanwhile, Hexproof says, " Your opponents can't target this permanent, but you can do whatever you like." Shroud's Problem : You can't buff or equip your own creatures, which simply feels weird to many players
While this ability is the most clearly weaker than Ajani Vengeant of all of his abilities, it is this ability combined with the ability to make mana that I think really makes the card
So, they are major wins for a lot of players, and major losses for others
Anthony Huynh's Blue-Black Faeries Faeries was a dominating deck during its time in Standard
Crucible of Worlds plus an additional land drop plus a way to mill yourself puts so many necessary effects into a single card that its hard to beat