How important is opening knowledge?


I see FMs and IMs playing rediculous to the level that they use the same opening all the time WITH BOTH COLORS! Chess teachers say :"Openings are like weapons, they are not everything". I think teacher telling bullshit to not lose students. Is anyone here above 2200 fide who can say something about the importance of knowing all the opening variations?


Masters just pwn because they know the pawn structures inside-out. They don't really need openings since technically everything you do is mostly based on where the pawns are. I'm guessing that since they're aware of the structures they can use the same setup on either side as long as they take in account being up or down a tempo. It's also why they're so good at blitz.