Exactly this. My last in-office job was an open floorplan where I had over fifty colleagues in my direct line-of-sight. The only conversations that took place in the open office were about sports or Game of Thrones—real work conversations happened in conference rooms (when they were available). One team decided to turn a small open area near my desk into their own "conference room", but the rollable whiteboards they used as "walls" didn't block any sound, especially from their speakerphone.