This basically boils down to Jund and Esper looking much less consistent and put together compared to the other two decks, although this might be (at least in part) because it's easier to build a cohesive artifact- or enchantment-themed deck than more abstract themes like "the top of your deck matters" or "lands matter." Here's a quick pros-and-cons list on the four decks
Hence, a total of 54 cards, featuring 4 suits, is typically present in a card deck
The rest of the drop tells his storyfragments of his legend, a sign the Ghost is somewhere on your table
Imagine this with Commander Eesha in play, as one example
Functionally, Yuna's Whistle is a pseudo-cantrip that always replaces itself with a creature, and finding the creature gives you some +1/+1 counters too, so there's combat trick potential as well