Long before Wizards of the Coast senior art director Ovidio Cartagena and his team of artists conjured up cavernous depths populated with jade merfolk and fungal tyrants, he would ride the bus back and forth to school each day in his hometown in Guatemala
First, those people who wants to get wildcards immediately are ones looking to make a specific construct deck
The entire article is worth a read for anyone who hasnt yet, since they also talk about designing and illustrating a new Pokmon
They are just filler cards
The beauty of rental programs is that you can switch cards whenever you want, so you can borrow some cards, play with them for a while, and, once you get tired of the deck you're playing, swap them back in for something else, as long as you don't go over your rental limit

2 Non-foil rare or mythic rare Booster fun cards from among the following: A rare (6.4%) or mythic rare (4.6%) showcase draconic frame card A rare (51.5%) or mythic rare (8.2%) borderless clan card A rare (21.5%) from among the borderless Sagas, Sieges, and lands or a borderless mythic rare Elspeth, Storm Slayer (0.7%) A rare (6.4%) or mythic rare (0.7%) borderless reversible dragon 1 Traditional foil rare or mythic rare Booster fun card from among the following: A rare (5.3%) or mythic rare (3.9%) showcase draconic frame card A rare (42.7%) or mythic rare (6.8%) borderless clan card A rare (17.8%) from among the borderless Sagas, Sieges, and lands or a borderless mythic rare Elspeth, Storm Slayer (0.6%) A rare (5.3%) or mythic rare (0.6%) borderless reversible dragon A showcase ghostfire frame card: A traditional foil ghostfire card appears 9% of the time