Others are pointing out that in the past, certain other promo cards have been locked behind having a Premium membership, which is itself a monthly paid subscription (albeit $12/mo, with other benefits)
Celebrate the third anniversary of theOne Piece Card Game with this special Japanese 3rd Anniversary Set a deluxe collectors box created to commemorate this major milestone with exclusive cards, premium accessories, and anniversary-themed artwork
At least Teferi, Ender of Friendships could be used, in theory, for something else, (even if no one actually does in real life.) Here, we all know what's about to happen
This card has more well-rounded utility compared to most of the other rare Lesson cards
Cool effect name
At the very least, Dowsing Dagger on an evasive threat is going to make you very happy in short order