Rerolling is the action of uninstalling and reinstalling the game to reset your account. This is so that you can "roll" the packs to get the card that you want, and it's doable since the game gives the players free gems right after the tutorial. Some cards are generally considered better than others, which is why in a game of chance, people tend to keep retrying until they get the good cards without having to spend any money.
When rerolling the game, there might be times when you get something good but not quite sure if you want to keep rerolling or not. If this happens, you can save your account by making a Konami ID so you can return to it if you don't get anything better.
Lower rating means that you should reroll, higher means that you should keep the card. This rating takes into account the card’s rarity and availability within the game. This rating is subjective with the consideration of the current meta.
These cards are considered to be among the best to obtain since they are very useful and effective in almost any deck.
people nowadays.. sigh asking the most basic things.. disn't even consult most walkthrough/help secttion and proceed to SHAMELESSLY EMBARASS THEMSELVES IN HERE for asking the most basic questions.. Hopeless tards..