As long as it doesn't become abandonware, I could certainly see this serving a niche segment of developers. There continues to exist a surprisingly large number of RAD tools on the market despite many having innate limitations that drastically limit their scope and applicability.
But they continue to exist because there are countless businesses demanding customized software for cheap. My thought is that a tool like this could very well be a welcome addition to the marketplace if it lowered the bar to entry of building web apps by a not-insignificant margin.
As long as DubJS isn't viewed as an effort to replace standard web app development, but merely another way for getting from A to Z that some developers find useful, I think it has a lot of promise!