I don't think this kind of demos are useless. They build in the minds of many spectators they are watching a very powerful person.
This attracts the ones seeking to have power and keeps away the ones looking for a fight, so it has some "martial" value.
BTW, there's a clip
of Ryusei Saigusa (Yoshinkan) performing various of these "tricks", including being raised by various uke and the group collapsing under him.
I agree with you, pretty much, about the usefulness of this kind of demonstration - although it is a great show! Still, it was an interesting response from Takeda in the light of the current conversation.