This is to javascript as rails is to ruby. (that might not be the best analogy, but better than bootstrap) While there is a UI portion, the reason it does not exist right now is because it's not meant to be solely a UI framework, such as Bootstrap. I don't think comparing it to bootstrap is, by any stretch of the imagination, reasonable. In fact, there shouldn't be any reason why you couldn't use Enyo in conjunction with bootstrap.
You can certainly use the CSS parts of Bootstrap with Enyo 2.0... I've been playing with that myself. Once we have new widgets, we're hoping to avoid the need to do a lot of CSS work to make great looking apps.
