it seems perfect for that - maintaining coherence over 30s-1min type window is achievable and so many ads are built on unrealistic premise to begin with.

To me, just reducing the cost alone seems secondary, far more important is putting the actual creative and marketing people directly in control of the output. Maybe the end result still gets sent to a pro studio for final production, but letting the true stakeholders directly create what they want could be a killer app. It may also be a terrible idea, like Homer Simpson's car - but that won't stop it being successful.