You can race them at the motards, but on the tracks that most of the racing is done, they will actually be slower into and out of the tights corners and flip flops., which is where all the gains are made and lost in motards. The only advantages are on Looooooong straights and fast bends which none of the go kart tracks have.
But they are a very cool looking machine, I just want one to put up on a stand in the lounge room so everyone can come over, drink beers and stare.