http://www.ubuntu.com/phone/developers

    If you’ve created HTML5 apps or mobile websites for 
    other platforms — there’s good news: the path 
    to Ubuntu 
    couldn’t 
    be quicker. We support both the Webkit/Blink and   
    Cordova development standards — and with a separate 
    API that enables
    websites to be quickly converted to run independently 
    of a browser, with full access to phone notifications 
    and 
    settings, the same goes for your web applications.

The more the better. As a consumer, I like choice. As a developer, multiple options means we move towards open industry standards rather than vendor lock-in and single points of control.