This app would make sense as an instant polling tool to give politicians instant, and evolving, feedback. So, this isn't direct democracy. In the current system, the representative is expected to vote on behalf of their constituents, using some level of personal judgment. This app would allow decisions to be made more quickly and better represent the view of the constituency.

Imagine being able to go back and see what the constituents demanded, and what the representative decided. One could then look at outcomes and determine how reliable a politician's judgment is.