It's one of those things that's done, IMO, because it looks good for demonstrations, and because it shows something specific (nothing wrong with with that). I wouldn't take it for a practical combat method, but that doesn't mean that it's "fake" either.
Anyway, he's showing (IMO) what happens when forces come into contact with a body conditioned for Aiki, and a somewhat more sophisticated relationship with the ground.
May be, here we can trace all the difference between what can be achieved by Tohei's Ki method (more linear, as I understand it) and S.Takeda's or Sagawa's body-education method with spiralling, whatever this may be. Anyway, I suppose Tohei wouldn't have been able to do that. I've seen him resisting several people pushing in a line but not doing this. And although there exists a video where Tokimune Takeda did apparently demonstrate this with his disciples, here some vague doubts creep in….
Could you or perhaps anyone else, please, correct me or elaborate on this?
More than curious,