The only limitation I can see is that consumers have to choose whether to display the playable cards or the art cards, but not both
It's risky, since it extends the effect to all players, but you've likely built your deck to take advantage of it most
Also probably
Rhystic Study Rhystic Study is a Blue Enchantment that allows its controller to draw a card whenever an opponent casts a spell at the cost of one mana of any color
While just enchanting things for value is a fine, fun way to play Estrid, the Masked, things can get out of control quickly if you start playing cards like Overgrowth and Fertile Ground so that Estrid's +2 acts like a massive ramp spell, and then The Chain Veil (perhaps enchanted with a Mask aura thanks to Estrid's 1) give you an easy way to activate your Estrid, the Masked an infinite number of times, potentially making infinite mana by untapping your lands and eventually winning with her Replenish ultimate
Most white decks are hungry for lands and cards because developing your mana and your hand at the same time isnt something theyre well suited to
