From what I´ve seen on the Discord channel, the Delight Emblems are not that bad.
Pretty solid % damage buff, and if you are lucky you get good secondary abilities - if not, then its a bit meh, but if you get things like Armor Pen, Daamge or Attack speed you shoudl be good.
Its a good thing there is not tank behind the paywall, though it would be nice to see a tank as a Cores purchase option, since that currency is not limited to RnG.
But it doesnt bother me, most likely we´ll see multiple tanks in the next event anyway so... *shrugs*