That's not really what it's about! It's not about achieving physical correctness or ray tracing. You can have a PBR renderer selectively break energy conservation for artistic reasons. It's not about ray tracing either. Current game engines like Unreal and Unity are considered PBR because they use a roughness/metalness workflow.

PBR about having maps that are easy to understand through physical analogy, and simplifying the workflow so that it's mostly shared across render engines, applications and pipelines. It's about the ability to create texture in Mari or Substance, which use rasterizing engines, and seeing the final render in Arnold look nearly identical.