Explainer demo, mainly used to explain how a process works, or how to do an activitiy or task that needs to be done. Very useful for retail products, memberships over the internet, webinars, etc.
Also to up load it in your You tube channel, or website.
Normally short format 2-3 minutes.
Also for E-learnig projects, business presentations and corporate videos.
The durantion for these uses is some times longer.