At the risk of sounding like an asshole. The themes on prebootstrap is pretty average at best. Alternatives like bootswatch.com offers far better themes.
Sure, but there is a bit of variety in this collection. bootswatch.com just look like different colour themes to me.
I took this as a quick intro to snippets of Bootstrap features. Ex: Logins and stuff. It does say "pre" bootstrap so I'm sure that was the intended purpose for this.