When a changed body is accelerated in EM field, it is just a macroscopic net effect of multiple interactions of charged particles in that body with the other changed particles outside. When we say "particle accelerator", it is still a simplification, because particle is not being accelerated in a sense like macroscopic body does, we just ignore individual interactions which increase the particle's energy. So I suspect that QFT shouldn't have a concept of "acceleration" of a particle on a fundamental level (not as an approximation). So my question is: if an "accelerating particle" (not accelerated particle) is something unphysical, why "non-inertial frames" should be considered something physical? Accelerated frame is a result of macroscopic averaging. Then could weird things like the Unruh effect be just an artifact of asking incorrect questions, like famous "what an observer riding a photon would see"?