Pokemon releases a wide variety of sealed products containing not only cards, but also accessories, posters, and other limited-release merch. They’re often only available in select locations with low-volume releases, making them rare on release. People tend to buy single cards from outside their original packaging, either when building for tournament play or a very specific collection item. 

Rarity looks different in the Scarlet and Violet TCG update, mainly to reflect all the various kinds of rarity that are available and to better identify them. As always, you can count on foil and holographic layouts and incredible artwork, but we’ll have to stay tuned for any future changes to the classification of card types and rarity. 

The short answer is yes, the Scarlet and Violet TCG update plays nicely in the sandshrew box with previous generations. While some features, mechanics, and stats from Pokemon found in regions outside Paldea have been changed, the changes aren’t so significant that they render your old cards obsolete. Train on!