People are actually not certain that they were able to fly because of how awkwardly they are shaped; mostly regarding the length of parts of their bodies and mass. There are a few 'scientific' articles about it somewhere. I read about it a while ago.
It's pretty cool looking but this is why I have a hard time accepting credibility from artists; To comment on how wasteful people are with electricity the artist makes something that consumes an immense amount of electricity for no purpose at all. Makes him just seem like a preacher type, "do as I say not as I do"
I love marsupials and other rodent-esque animals but kangaroos scare the crap out of me for just this reason. It's more the back legs that I worry about, it's like putting knives on a cannon ball and smacking people in the gut with it.