Because there are so many and most decks dont want many, you can get as many as you want in the second half of the pack most of the time
A bigger magic deck can dilute your best cards, which reduces your chances of drawing them at the right time
Mangara is certainly the stronger of the two cards, discouraging your opponents from attacking by granting you an extra card advantage if they attack with two or more creatures, or letting you draw a card when an opponent casts their second card each turn
6 Fain, The Broker Trade You For A Treasure Theres a lot going on with Fain, the Broker, given its four abilities and toolbox-like uses
That said, though, Shroud is still beloved by some of us old-schoolers, especially when it's on a Shroud card like Lightning Greaves, where its Equip cost of 0 makes it more than justifiable, even with the inherent downside of not being able to target our own creature afterward