Although it would be better if it could attack all the exerted characters too, this would prevent a player from protecting cards from challenges by keeping them readied
[3] If 3 or more "Morganite" Spells with different names are in your GY and/or banishment: You can make the ATK of all monsters your opponent controls become 0
If you have a 60-card deck and your opponent has a 40-card deck, you can add 20 GY to him, but as the number of decks increases, the probability of not being able to draw this guy also increases
Bloomburrow itself is a very two-color centric format, with some slight splashing, so doing more gifting of treasure would have been hard to pull off in such an environment
All of these cards enter at the same time
This is why people back in the day used to sub the same card on repeat until they got a different grade they wanted (when you could grade for $10)