This typically occurs when a seller is selling a sealed booster box and takes pictures to make the box look like its in better condition than it is, omitting a tear in the exterior plastic or damage beneath the shrink wrap
Collectors' forums are great for finding deals or trades
The same applies for your combo staters and extenders as they are the cards that let you play the game, so if you dont see them in your opener, you are likely to lose
References 2017-01-29 | 54th Aichi CS (Individual Battle) 2017-01-29 | 54th Aichi CS (Team Battle) (1st, 2nd, 3rd) 2017-01-29 | 7th Daybreak Cup ~New Year Party!~ 2017-01-29 | 1st Hobby Station Ikebukuro CS with Hatti CS 2017-01-29 | Hatti CS Heavy Storm Cup in Kitakyushu (Team Battle) (1st, 2nd) 2017-01-28 | Hatti CS Heavy Storm Cup in Kitakyushu (Individual Battle) 2017-01-28 | Tokyo Yu-Gi-Oh
It can also protect your creatures of the chosen type from being countered, which can be very powerful
Each era introduces new mechanics, card designs, and collectible symbols that enrich the game