A video documentary dealing with a project where a new product or equipment is developed can be an asset on a number of levels.
Firstly, projects can always be done better. A critical look at where a project succeeded and failed, if documented and reviewed, can be a valuable tool when subsequent projects are undertaken. Unfortunately written reports of this kind are rarely read once they have been written. On the other hand a well made documentary is engaging and makes learning easy.
Secondly, a short documentary showing your company's professional development and project management skills, utilised in delivering a new product, can be a powerful selling tool with prospective customers who are not aware of your capabilities.
Lastly, if a documentary has carefully planned shots it can be reedited at relatively little extra cost into a shorter promotional video.