When was the last time you saw, outside of manga/anime or more obscure science fiction novels, somebody putting their brain in a jar, and putting that jar in a non-humanoid body?
I think that's the only place where you would typically see this. This concept reminds me of the cymeks in the Dune prequel series. I do see your point though. Who among us wouldn't want to trade our bodies in for a huge hexapodal machine capable of space flight?