Originally Posted by Foyn

..should save this somewere^^
but wuts the lv50 thing about?

If your reach Lvl50 (or get 1mil SED) you get ExLvls enabled. They're extra lvls you can raise your cards above 100.

Once those are enabled, getting a maxed card will raise ExLvls. And getting an Ex maxed card will give you a WC of the same rarity, instead of leveling up another card.
On one hand, this is good when having non-maxed cards of the same rarity, as you can personally choose which one levels up. However, those WCs can't be used on maxed cards to raise ExLvls, and you have 0% chance of a card of better rarity being raised.