Why Enyo? HP's Kevin Schaaf explains why [video]
It's one thing to convince a developer that they should make an app for a specific platform isn't usually a hard affair. There are obvious reasons to develop apps for iOS or Android, and the most obvious of those is the fact that there are lots and lots of potential users. But convincing a developer which framework they should use? That's a different matter. Realistically they could use the platform-native framework, but if you're wanting to target multiple platforms (iOS, Android, Windows Phone, webOS, and web browsers on all devices) by just developing one app, there are only a few options worth considering.
Source: The Enyo Blog