We did this for us. Really! We used to work with banner production and the creation of DCM campaigns. We noticed that there was no good tools to help with the creation process when you needed to do 100+ versions in 20 different sizes unless you wanted to serve the ads in a 3:rd party system.
As veterans in ad tech we know that there are several issues with 3:rd party serving such as walled garden with data, loss of clicks and impressions and huge costs in campaigns with a lot of impressions.
We had earlier built a system that enabled dynamic video advertising so we created a new team that focused on building a tool that we could work in.
The mission was to create a system that would support both the creative part of making html5 ads, such as animations, asset handling and a interface that designers would like.