Lots of fun sacrifice themes, death triggers and semi-Birthing Pod style builds can come to fruition when you tribute monsters to summon your bigger monsters
Refuse is more niche, but if your playgroup has infinite mana combos that end with giant Exsanguinate / Comet Storm / other X spells, then you can answer it with Refuse and kill them instead
Credits meanwhile have a singularly focused goal, allowing the player to trade them in for new cards, or new appearances for cards, and are earned by opening duplicates
One final point to mention is that this app, on Android at least, doesnt seem to work on any of the dozens of devices we have on hand
You can use booster boxes when you want a larger opening session and more cards from one release
Fast Sample Delivery: Sample orders available with a lead time of 7-12 days