A couple of things I really liked about the " manifesto" is two,points he brings up, the unspoken:
1. How hard it is for most beginners to learn clipped in, and how they are hammered on about how important it is to ride that way unless you are a downhiller and
2. Crashing while clipped in is likely to result in more/bigger injuries. Already I've gotten very comfortable in falling feet first; coming off my bike on my feet where I iChat have otherwise landed on a wrist or shoulder.

I know, I totally sound like I drank the Koolaid. I wish I'd changed several years ago when it was first suggested to me.