Despite releasing a major update on December 21st, the player numbers only spiked for around a week before returning to similar levels. This update added the ability for players to level up their account and receive rewards, including card packs for free. Evidently though, the game has more serious issues at play than just progression – such as the $19.99 / £15.99 entry fee, market based monetization approach resulting in a strong ‘Pay To Win’ feel, RNG heavy gameplay elements and the game’s long drawn out matches.
That kind of all matches the scuttlebutt that I've heard; I haven't tried it myself but I've definitely seen complaints that the RNG stuff can make for big shifts in victory likelihoods despite one player being "better." I haven't tried it myself but I'm guessing it'll go free-to-play or at least something I could spend 5 bucks on and get a few hours out of at some point. $20 is too much for a game that has mixed reviews still.