This is mostly to avoid the look of impropriety, as being able to see the back of the card means theres the possibility of marking (i.e., putting marks on certain cards so you can tell when they pop up in your deck without drawing/scrying them)
5 "Dragon Vault" Has Surprisingly Baffling Prices Price of a Booster Box: N/A "Dragon Vault" is a rather odd set for the Pokmon TCG
As in, many of the uncommons are of the caliber of the rares of many other sets
the PVC holder can easily carry printed Entrance tickets, floor plans, menus, and anything else you can think of
Once per turn (Quick Effect): You can detach 1 material from this card, then target 1 face-up Xyz Monster you control and 1 "Utopia" monster in your GY
Collector Boosters For fans who want it all, Collector Boosters are the easiest way to add the coolest cards to your decks and collection