The cards are sold via one-time deals you buy them now, or face the secondhand market later on
While the article leads to more questions than answers, it clarifies this version of a playtest card is created in a brand-new way, unlike the ones seen in Mystery Booster products or Gavin Verheys special events at MagicCons
Id like this rogue more if it could get more counters on its own, though it stands as a reasonable threat for 4 mana
Seriously, nearly every card thats ever broken the game has been related to cheating mana or something similar
For simplicity's sake, I'm representing these in a bullet-point format, but if you're looking for additional effects to round out your lists with some variety, you should consider some of these
Hour of Reckoning, Utter End, Crackling Doom removal to clear the board when the odds turn against you