The only use I can see this being any good for are the sky surfers. Rail Grinding in a pair of shoes doesn't really work, otherwise, we could save ourselves the rolerblades/skateboards/etc. and all just go giver shit on the curbs in our sneakers!
There is an excellent picture in this months Skydiving of a guy busting his ass big time trying to land with roller blades on. I predict that we will see some spectacular ass busting shots if the rail thing actually gains any popularity.