...and I guess your next comment will be 'why not just rent a Kona for 2 weeks' and you're probably right, but at the same time, back in the 80s, mobile phones were ridiculously heavy and naff, and people said 'why not just find a phone box'. They had a point back then, and yet now there are almost no phone boxes left.
Point I'm making is, it's interesting to see people come up with these things, and even if they fail, eventually they'll find ways to make better and more useful versions. Eventually some evolution of that idea (extended range battery packs on EV cars) will simply be the best option, but rarely starts that way. Such is progress.