TL;DR: These decks are expensive, so just make a judgment call if you really want one or more
Having the flexibility to discard a high mana value card you currently cant cast to draw something better and a few turns later putting that card back in your graveyard from exile at instant speed feels like a great mechanic
Duplicant Would you rather pay 1 mana more for the flexibility on Meteor Golem, or have the more restricted removal ability on the cheaper-to-cast Duplicant
A: Check rarity symbols, card condition, and demand through price guides like TCGPlayer or eBay sold listings
For a two-mana walker, that kind of long-term control is honestly a little rude but it is also exactly what makes Wrenn and Six one of the best planeswalkers in MTG
Cavern of Souls Land As Cavern of Souls enters the battlefield, choose a creature type