whats the deal with this opening


I assume you mean "How to deal with this opening" and it's really a solid opening for both sides. Just play basic chess opening principles like described in this blog post of mine:
https://www.chess.com/blog/KeSetoKaiba/opening-principles-again
In your position, the main thing is the g7 bishop attacking the center (d4 square in this case). White will try to develop pieces and maintain control of the center (moves like Be3 or Nf3 to develop and support d4) and black will try to develop in ways to fight for control of the center (moves like ...c5 or ...Nc6).

no i dont undestand why people play it all the sudden
Oh, yeah, some openings go through phases of popularity. I've also had some days where I play online and everyone seems to randomly play the exact same variations against me. It's just variance. Statistically, that will occasionally happen, so we probably just remember when it happens and not the times it doesn't.