This brilliant idea for a bridge has got to be the funnest example of crossing from on place to another that I have ever seen. It brings an element of unique fun to a concept that is traditionally fairly mundane. It completely changes how you get from A to B, reinventing a conventional way of travel. This is what a good design should do. It might not be the most efficient way of crossing the river Seine, it might not even be the safest, but people are drawn to such ideas and the use of such structures is all but guaranteed.