because you don't feel G's in the sim
737 endorsement was ZFT. First line training session with a pax load differed only in three major respects from the sim sessions ..
(a) the aircraft was considerably easier to fly
(b) the aircraft visuals were far better and should be mandated for the sim
(c) it was much more fun
In every sim session, after a few minutes, I was sufficiently immersed in the doing to have difficulty distinguishing it from the aircraft IMC. Visual sim flight was always a tad surreal.
Perhaps that was just a reflection of my seat of the pants incompetence ?