It's not really anything special, other key resellers like Eneba, Kinguin, Gamivo, etc. also offer EU4 for just under 2$, all year round.
If a member of the staff is reading this: I am curious to know what is paradox's opinion about these websites. Should customers straight up avoid buying from them? Is it any better than pirating the game? The keys seem legit (they activate on steam), but the prices are way too low, so something is probably shady there.