As a developer I can build out an interactive prototype from designs much much faster than by just using jQuery, so I am an audience for this. Proving out interactions early is (usually) much more important than having re-usable code at the start of a project..

Our designers - who know enough code to make use of this tool - can prototype interactions from their designs without asking a developer to help them. They are an audience for this.

Are we really going to have another "why do we need this automation tool when we can do this by hand?" conversation yet again on Hacker News?